Tom Castelein

Personal Income Tax Expert

Tom Castelein reviews the blogs for PIA Go! and safeguards the quality of each article’s content. With more than 10 years of experience in accountancy, taxation and business advisory, he combines in-depth expertise with a strong practical approach. Tom obtained a bachelor’s degree in Accountancy-Taxation and Marketing at Artevelde University of Applied Sciences in Ghent and supports self-employed professionals and SMEs daily with financial, tax-related and strategic questions. Thanks to his expertise, he ensures that PIA Go!’s content is accurate, relevant and aligned with the reality of entrepreneurs.

Je zorgt voor je eenmanszaak. Maar zorg je ook voor jezelf?

Als eenmanszaak ben je vaak tegelijk ondernemer, planner, boekhouder, verkoper en marketeer. Je agenda loopt snel vol en voor je het weet staat alles op de eerste plaats… behalve jijzelf. Nog snel een mail beantwoorden. Die offerte afwerken. Een klant terugbellen. Het hoort allemaal bij ondernemen. Maar wanneer sta je nog eens stil bij je eigen welzijn? Zelfzorg klinkt soms als iets vaags of luxueus, maar eigenlijk is het heel simpel: hoe zorg jij ervoor dat je goed blijft functioneren terwijl je een zaak runt?

PIA Go! vs Astro Online Accountant: which accounting solution for your sole proprietorship?

When running a sole proprietorship, your main goal is a reliable accounting system without spending excessive time on it. Today, many digital solutions promise to simplify this process. PIA Go! and Astro Online Accountant both offer online accounting services. However, their approach and the way they support entrepreneurs differ significantly. Here are the key elements to consider when choosing the solution that best fits your situation.

PIA Go! vs Dexxter: which accounting solution fits your sole proprietorship?

As a sole proprietor, you mainly want one thing: accurate accounting that does not take up all your time. Fortunately, there are many digital solutions available today to help you with this. Some focus primarily on managing your accounting yourself through software, while others offer a combination of a user-friendly tool and personal guidance. But which one best fits your way of doing business? We are happy to explain the difference between PIA Go! and Dexxter: two popular accounting solutions for Belgian sole proprietorships. Not to point out a single “winner”, but to help you choose the approach that best matches your needs and preferences.

PIA Go! vs Accountable: which accounting solution fits your sole proprietorship?

As a sole proprietor, you mainly want one thing: accounting that is accurate without taking up all your time. Today, various digital solutions exist to support you. Some allow you to manage everything yourself via software, while others combine digital tools with guidance and follow-up.

Why you should choose PIA Go! for your sole proprietorship

Running a sole proprietorship means wearing many hats: entrepreneur, salesperson, marketer, and administrator all at once. It’s no surprise that you’re looking for an accountant who takes your business seriously and ensures your bookkeeping is correct. Unfortunately, choosing the right accountant isn’t always easy. Do you go for a large accounting firm? A digital solution? Or something in between? One thing is certain: at PIA Go!, we believe sole proprietors deserve a tailored approach. And that’s exactly what makes the difference.

Are you sleeping well as a starting sole proprietor?

As a starting sole proprietor, sleep is sometimes something you “catch up on later.” First one more email, then that quote, and oh yes: your accounting… Before you know it, you’re lying in bed with a mind that keeps spinning like a browser tab you can’t close. And yet, almost everything starts with sleep. Not because some health guru says so, but because without a good night’s rest, you’re simply less sharp, less cheerful and less yourself. And that just happens to be your greatest asset in your business.

Fines up to €5,000 from 2026: how to avoid Peppol stress as a sole proprietor

Are you still using paper invoices or PDFs via email as a sole proprietor? Then now is the time to take action. From January 1, 2026, Peppol will become mandatory for B2B invoices in Belgium. This is established in the Royal Decree of July 14, 2025. If you’re not compliant, you risk fines of up to €5,000—even as a sole proprietor. In this article, you’ll discover what Peppol means for you, whether it applies to your situation, and how to avoid penalties (without technical hassle).

Buying a Second-Hand Car as a Sole Trader: What Can You Deduct for Tax Purposes?

Buying a brand-new car is not always necessary or financially possible. Many self-employed professionals operating as sole traders therefore opt for a second-hand car. This choice is often financially attractive. However, the tax treatment is a bit more technical. What about VAT? What share of the costs can you deduct? And how should the purchase be recorded correctly in your accounts? Here is what you need to know to avoid any issues during a tax audit.

Meal vouchers for self-employed individuals: how does the taxation work?

Meal vouchers are best known as a popular extra-legal benefit for employees. But did you know they can also be interesting for you as a self-employed individual with a sole proprietorship? There is, however, an important nuance: your sole proprietorship cannot grant meal vouchers to yourself. You do not pay yourself a salary in the legal sense of the word. Meal vouchers only come into play once you employ staff.

Gift vouchers in a sole proprietorship: what about tax and VAT?

Offering gift vouchers is a popular way to thank clients, employees, or business partners. It’s simple, flexible, and easy to use. From a tax perspective, however, the situation is slightly more technical. What about VAT on gift vouchers? Can they be recorded as professional expenses in your sole proprietorship? And how should you record them correctly in your accounting? Here are the key rules you need to know to use gift vouchers with confidence, without unpleasant surprises during your next tax return.

Fuel card for sole proprietorships: convenience, overview and tax advantages

A fuel card is a small effort with great convenience for many self-employed individuals. You no longer need to collect receipts, you receive one clear invoice and you can accurately track your consumption. But how does the taxation of a fuel card work for your sole proprietorship? In this blog, you will learn about the benefits, how VAT deduction works and what to consider to correctly record your fuel expenses.

Lease car for your sole proprietorship: how do VAT and taxation work?

Leasing a company car is popular among self-employed individuals today. You spread the cost, maintain liquidity and still drive a new car. But how does VAT, tax deductibility and fiscal rules work when you lease a car for your sole proprietorship? In this blog, you will read what car leasing entails, what you can deduct and what to watch out for to avoid unpleasant tax surprises.

Using your own car for your sole proprietorship? Here’s how the deduction of car expenses works

Do you use your private car for business trips as well? Then you naturally want to know which costs you can deduct. But be careful: for sole proprietorships, this works differently than for employees or company directors. We list the main rules for you.

Je klanten bedanken? Zo zit het fiscaal met relatiegeschenken en representatiekosten

A bottle of wine for a loyal client, a year-end gift with your logo, or a lunch to celebrate a successful collaboration—these gestures are often appreciated. But how should they be treated for tax purposes? Are business gifts deductible? Can you recover VAT on champagne or gift vouchers? This article explains what is allowed (and what is not) when it comes to representation expenses and business gifts, so you can maintain strong relationships with your clients without unpleasant tax surprises.

Running an online store? Here’s how to automate your sales administration

You’re launching an online store. While this type of business offers a lot of freedom and flexibility, it also generates a high volume of transactions to manage. Fortunately, a large part of this administration can be automated. This article explains how to automatically integrate your online sales into your accounting, so you can focus on growing your business.

Following a training with the SME portfolio? Here’s how to book it in PIA Go!

Are you taking a course with subsidies from the SME portfolio? Smart move! You get up to 40% discount and invest in your own development. But how do you process these subsidized costs in your bookkeeping? In this blog post, we explain it step by step.

Deducting your home office for tax purposes? What you can do… and what to avoid

More and more self-employed professionals work at least partly from home. You may even have set up an entire room as an office or created a workspace in your living room. This immediately raises a tax question: can you deduct your home office as a business expense? Which costs are allowed? And what about VAT? This article explains the rules that apply to a home office for sole proprietors, what is permitted, what is not, and how to apply these rules correctly.

Deducting Internet expenses in a sole proprietorship: what is allowed and what is not

Are you self-employed as a sole proprietor? Let’s be honest: the Internet has become indispensable. You use it to send quotes, issue invoices, contact your clients or manage your online store. But how should these costs be treated from a tax perspective? Can you deduct everything or only part of it? And how should you record them correctly? This article explains the rules applicable to Internet expenses, GSM subscriptions and their tax treatment.

Niels den Boogert from De Cocktailfiets: “PIA Go! is a user-friendly accountant that truly thinks along with you”

For Niels den Boogert, founder of De Cocktailfiets, one thing was clear from day one: he didn’t want to handle his bookkeeping himself. “Accounting was one of the first things I outsourced. I want to focus on clients and events, not numbers. PIA Go! combines everything I need: a user-friendly tool and an accountant who thinks along with me. That gives me confidence.”

Tax return for sole proprietors: what you need to know

Becoming self-employed offers more freedom and flexibility, but it also comes with greater administrative responsibilities. Your tax return is one of them. For a sole proprietorship, this is done through personal income tax. This return includes all your income and allows the tax authorities to calculate the tax due. Understanding how it works helps you avoid mistakes and manage your tax situation more effectively.

Stijn Doumen (Onweer): “PIA Go! is my accountant and my peace of mind”

Starting your own business brings great freedom. But entrepreneurship also comes with a very concrete reality: administration. For Stijn Doumen, freelance producer and musician in the project Onweer, this aspect was a real challenge. His passion is music, not accounting. After several rejections from traditional accounting firms who considered him “too small”, he eventually found a suitable solution with PIA Go!. Today, he sums up his experience in a few words: “PIA Go! is not just my accountant. It is my peace of mind. I can let go and fully focus on my music.”

The importance of a financial plan for your sole proprietorship

As a self-employed individual without staff, it is essential that your business is financially healthy. At PIA Go!, we help you create a financial plan that is fully tailored to your situation as a sole proprietorship. This way, you are stronger, you spot growth opportunities faster and you avoid unpleasant surprises.

Loss in a Sole Proprietorship? Here’s how to declare it correctly

A year in which your expenses exceed your income can happen—even in a well-managed business. This situation is not unusual, especially during the start-up phase or after a significant investment. In fact, a business loss can offer a tax advantage. When correctly declared, it can reduce your taxable income. Discover how losses are treated for tax purposes and how to declare them properly to avoid issues with the tax authorities.

Start-up capital invested in your business? Here’s how to record it in PIA Go!

When starting your business, it is common to inject your own funds to cover the first expenses. But how should this start-up capital be recorded in your accounting? Discover the procedure to follow in PIA Go!.

A business bank account as a self-employed person: must or option?

“Do I need to open a separate business account as a self-employed person?” This is a question we often receive at PIA Go! The short answer is: no, it is not legally required. But it is a good idea. In this blog post, we explain why.

Received a notice about a missing intra-Community listing? Here’s what to do!

Have you received a letter from the VAT administration about a “missing intra-Community listing”? Then you might be wondering what exactly you need to do. In this blog post, we explain how to resolve the situation quickly and correctly.

Insurance for self-employed professionals: which ones are tax deductible?

Every self-employed professional naturally wants to be well insured against risks. Some insurance policies can also help reduce your tax burden. However, not all premiums are deductible. Which insurances can be recorded as professional expenses, and which are considered private costs? Here are the rules to help you build an insurance package tailored to your situation.

Loan concluded? Here’s how to record received amounts and repayments in PIA Go!

Have you taken out a loan to finance your business? This is an important step in the life of a company. Loans are a common source of financing for entrepreneurs, but their accounting treatment often raises questions. How should you correctly record the amount received? And what should you do when you start repaying the loan? Here is, step by step, how to handle these transactions in PIA Go!.

VAT exemption scheme: an advantageous option for your business?

If your annual turnover remains below 25,000 euros, you may be eligible for the VAT exemption scheme for small businesses. At first glance, the formula seems appealing: no quarterly VAT returns, lighter administration and no VAT to charge. However, this simplification is not always the most advantageous solution. It all depends on your activity, your clients and your professional expenses.

Have you received a fine? Here’s how to record it in PIA Go!

A traffic fine issued in your company’s name, a penalty for a late VAT return, or another administrative sanction… it can happen. In that case, one question often comes up: how should you correctly handle this expense in your accounting? The answer is simple, but the tax rule that applies is specific. Here’s what you need to know.

What happens if you cannot work due to illness as a self-employed professional?

Being self-employed offers a great deal of freedom, but it also comes with greater responsibilities. What happens if you suddenly can no longer work because of illness, an accident or the birth of a child? The good news is that self-employed professionals are also protected. In certain situations, you are entitled to sickness or maternity benefits through your mutual health insurance fund. Additional insurance policies can further strengthen this protection.

Why your mutual health insurance fund is essential when starting as a self‑employed sole trader

Starting a sole proprietorship involves many steps. You need to organise your administration, find your first clients, arrange your social security contributions and set up your accounting. Another important step is planning your protection in case of illness or unexpected events. Joining a mutual health insurance fund is one of the first actions to take.

Your foreign supplier still charges VAT? Here’s how to resolve the situation in PIA Go!

Have you received an invoice from a supplier based in another EU country that includes foreign VAT? In principle, this should not happen. In transactions between businesses located in different EU countries, VAT is normally not charged by the supplier. Yet, this situation does occur. Here’s why it happens and what you should do if you receive an invoice with foreign VAT.

Filing your VAT return? With PIA Go!, it’s that simple!

The deadline for your VAT return is approaching and you have never filed a return yourself? Don’t worry. With PIA Go!, the process is much simpler than it seems. In this article, you will discover how to quickly and correctly submit your VAT return.

Do you import from countries outside the EU? Here’s how to record it in PIA Go!

Do you import goods from countries outside the European Union, such as China, the United States, or the United Kingdom? If so, you will quickly encounter customs duties, import VAT, and customs clearance fees. How should you correctly record these costs in your accounting? This article guides you through the process step by step.

Car expenses: lump sum or actual costs? Here’s how to record it in PIA Go!

A car is often indispensable for your business, but how do you deduct the costs in the most advantageous way? And what about the well-known CO2 deduction limitation? In this blog post, we guide you through the tax rules for car expenses and show you how to get the maximum out of your deductions.

Working from home? Here are the housing expenses you can deduct for tax purposes

Do you work from your living room, your home office, or even your garden? This situation has become very common. Many self-employed professionals now run their business from their home. In this context, one question often arises: can you deduct part of your housing expenses as business costs? The answer is yes, provided that you comply with the tax rules. Discover which expenses can be taken into account and how to calculate the professional-use percentage.

Have you incurred expenses before launching your business?

You have started a sole proprietorship, but some expenses were incurred before the official launch of your activity. You may have bought a laptop a year ago or taken a course before becoming self-employed. These expenses can often still be recorded as professional costs. Here’s how to correctly register these pre-launch expenses in PIA Go!.

Received a purchase invoice with a discount?

With a bit of luck, as a self-employed entrepreneur you will sooner or later come across discounts on invoices. But did you know that there are different types of discounts, each of which must be handled differently in your VAT processing? In this blog post, we show you how to correctly record each type of discount in PIA Go!

Recording sales in PIA Go! How to create invoices, credit notes and more

Yes, your first sale is in! But how do you make sure it is properly recorded in your administration? In this blog post, you will discover how to quickly and easily create invoices, register daily receipts and keep your sales administration in order via the ‘Sales’ menu in PIA Go!.

Recording foreign purchases in PIA Go! Everything about intra-Community acquisitions

Do you purchase goods or services abroad? Then different VAT rules apply compared to domestic purchases. In this blog post, we make the international VAT jungle much clearer. You will discover how to correctly record foreign purchases in PIA Go! and why these rules exist.

Getting Started with PIA Go! Everything you need to know about your digital accounting

Submitting VAT returns and preparing profit and loss statements is not something most entrepreneurs look forward to. In this blog post, you’ll discover how PIA Go! makes tax administration simple and clear, so you have more time for what you actually enjoy doing.

Getting Started with PIA Go! Everything you need to know about your digital accounting

Submitting VAT returns and preparing profit and loss statements is not something most entrepreneurs look forward to. In this blog post, you’ll discover how PIA Go! makes tax administration simple and clear, so you have more time for what you actually enjoy doing.

Getting Started with PIA Go! Everything you need to know about your payments and invoices

Money flows in and out of your account, but do you always know exactly where your business stands? The “Payments” menu in PIA Go! allows you to keep a clear overview of your financial situation without having to go through bank statements or manage spreadsheets. In this article, you’ll discover how to easily track your payments and balances.

Recording purchases in PIA Go! How to process purchases, investments and more

New business, new invoices… and new expenses! But how do you record those expenses in a tax-efficient way? In this blog post, we dive into the “Purchases” menu in PIA Go! and show you how to manage your costs properly.

Deductible expenses for self-employed individuals: a practical overview

Smart entrepreneurs keep their tax matters in order. By making optimal use of deductible expenses, you retain more money for what truly matters: growing your business. But which expenses can you actually deduct? In this blog, we provide an overview of the main deductible costs.

Deductible travel expenses: optimise the tax treatment of your business travel

Do you travel frequently for your business? Transport costs can then represent a significant part of your budget. The good news is that a large portion of these expenses can be recovered through your tax return. However, it is important to understand the rules that apply to each mode of transport. Here’s how to optimise deductions related to your professional mobility.

Deductible representation expenses: networking with a tax advantage

Business lunch? Year-end gifts? The tax authorities always take a share. Still, maintaining relationships is crucial for your business and can also offer a nice tax benefit. Discover how to use business meals, gifts and other networking expenses smartly to reduce your tax bill.

Deductible marketing expenses: how to optimise your advertising costs for tax purposes

Without visibility, it’s difficult to attract customers. Without customers, no business can grow. That’s why most entrepreneurs invest in promoting their products or services. These expenses also offer a tax advantage. In most cases, marketing costs are largely deductible—provided you apply the tax rules correctly. Here are the key principles to understand.

Deductible expenses for your workspace and home office Real tax benefits

Do you work at your kitchen table, or do you have a dedicated home office? Your workspace can also have a positive impact on your tax return. If you carry out your activity fully or partially from home, you can deduct part of your housing expenses. This article explains how to take advantage of this.

Deductible costs for professional services: tax advantages for expertise

No entrepreneur can do everything alone. You rely on experts, pay insurance premiums and invest in your knowledge. Good news: most professional services are also tax-efficient! In this blog post, you’ll discover how to maximize the deductibility of professional services.

Office supplies and IT: which expenses are deductible?

From your laptop to your last pack of paper: your office and IT expenses often represent a significant part of the budget of a self-employed activity. Good news: most of these costs are tax deductible. Here’s how to treat them correctly in your accounting.

Deductible internet and phone expenses Optimize your tax advantage

In today’s business environment, where you need to stay reachable at all times, your phone and internet connection are essential work tools. The costs related to your smartphone, landline, and internet subscription can add up each month. The good news? Part of these expenses can be recovered through your tax return. In this article, discover how to optimize the tax deductibility of your telecom expenses.

Deductible expenses for self-employed individuals: what can you deduct?

As a self-employed individual, you naturally want to manage your taxes smartly and optimize as much as possible from a fiscal perspective. But how does it actually work? The basic rule is simple: all costs you incur for your professional activity are deductible. However, as with many tax topics, there are some nuances. We’ve listed the key points so you can make the most of your deductions.

Credit notes in your VAT return: how to handle them correctly

An incorrect invoice, returned goods, or a commercial correction: all of these situations can lead to a credit note. But how should you correctly process it in your VAT return? The answer depends on one key element: did you receive the credit note from a supplier, or did you issue it yourself to a customer? The rules are not the same. Here is how to proceed.

Filing your VAT return yourself: a practical guide

Does the mere thought of your VAT return already stress you out? You’re not alone. Every self-employed professional must submit a VAT return at regular intervals. But where do you start? How does it work? And what should you pay attention to? This practical guide helps you get a clear overview.

Doing your own bookkeeping as a sole proprietor? Here’s how to get started the right way

You run a sole proprietorship. A question quickly arises: should you outsource your accounting to a professional or manage it yourself? In Belgium, hiring an accountant is not a legal requirement. Many starting entrepreneurs therefore choose to manage their own administration. But where should you start? What are the key points to keep in mind? And which option best suits your situation? Here are the basics to help you get started properly.

Becoming self-employed as a side activity: advantages and points to consider

Do you want to generate additional income alongside your fixed job through your personal project? Or gradually take the step into entrepreneurship? Becoming self-employed as a side activity is an interesting intermediate step. What are the advantages, and what should you pay close attention to? Here’s a clear overview.

How much does a side-business entrepreneur earn?

You may know someone who runs a side business and have asked what they actually keep from it. The answer is often… a bit ironic. The gap between revenue and what remains in your account can be significant. So what can you realistically expect when starting a side activity? And where does part of your revenue go? Here are the main taxes and contributions to consider.

How much can you earn as a self-employed person with a secondary activity?

“How much can I earn from a secondary activity?” This question often comes up among entrepreneurs who are considering starting a business alongside their salaried job. The answer is simple: there is no legal limit. In a secondary activity, you can earn as much as you want. However, there are a few points that deserve your attention.

Starting as a self-employed person with a secondary activity: what you need to know

Are you considering starting your own business while keeping your current job? Many entrepreneurs choose this option to test an idea, build a client base or generate additional income without immediately leaving their salaried position. The status of self-employed with a secondary activity allows exactly this combination. Before getting started, it is useful to understand the rules and obligations that apply.

Deductible administrative expenses How to turn mandatory costs into a tax advantage

Every entrepreneur faces various administrative obligations—and the costs that come with them. The good news? Most of these expenses are 100% tax deductible. In this article, discover how to turn even the most common administrative costs into a tax advantage.

Deductible expenses for self-employed professionals The complete guide

When starting your business, you naturally want to make the most of the available tax advantages. One of the most effective ways to reduce your tax burden is to correctly apply the rules on deductible expenses. This article outlines the key principles.

Reverse charge VAT: what you need to know

If you work in the construction or renovation sector and invoice your services to other companies, you have probably already encountered the concept of reverse charge VAT, often also referred to as the “co-contractor regime”. Since 1 January 2023, the mandatory wording on the relevant invoices has been modified. Here is what you need to know to remain compliant.

Simplified accounting: a practical guide for starters

Are you starting as a sole proprietor or running a small business with an annual turnover below €500,000 (excluding VAT)? In that case, you can opt for simplified accounting. This system does not require double-entry bookkeeping. However, you still need to comply with several basic administrative obligations. What exactly do you need to record?

Classifying your expenses correctly in your VAT return? Here’s how to do it.

Even if you run your activity as a side business or have just started your sole proprietorship, you must submit a VAT return. You must also allocate your expenses across different categories. This classification is essential to correctly declare VAT and recover deductible VAT. But concretely, which expenses should be included in each category? Here are the rules to follow.

Daily revenue journal: easily track your sales

Do you regularly sell to private customers as part of your business? You might wonder whether you need to issue an invoice for every sale. That’s not always necessary. The daily revenue journal offers a practical alternative. This article explains what it is, when to use it, and how to maintain it correctly.

Recording gift vouchers correctly: the right approach

Do you sell gift vouchers in your business? Their accounting treatment must be correct from the start. The complexity lies in the fact that tax authorities apply different rules depending on the type of voucher. Here are the key principles.

Side activity: easily apply for your enterprise and VAT number

Are you planning to start a side business? Do you want to turn a passion into extra income or offer your skills alongside your main job? A few administrative steps are required to get started. Two are essential: obtaining an enterprise number and activating a VAT number. This article explains how to proceed.

VAT on recharged expenses: this is the smartest approach

Do you sometimes recharge costs to your clients? Smart move! But did you know that specific VAT rules apply? If you choose the wrong approach, you may leave money on the table. In this blog, we explain how to structure recharged costs in the most tax-efficient way.

Accounting for self-employed individuals in a side business: how to approach it

Just started as a self-employed individual in a side business? Then you probably already know that you are required to keep accounts. But did you also know that accounting doesn’t have to be as complicated as it sounds? As a self-employed individual in a side business with a turnover below €500,000, you can opt for a simpler approach…

Make an impression with your first invoice (and get paid faster)? Use PIA Go!

Sending your first invoice as a self-employed professional or sole proprietor? That’s always exciting. What exactly do you need to include? How do you make sure everything is correct? And more importantly: how do you get paid quickly without turning it into an administrative nightmare? No worries—with PIA Go!, you can create a correct and professional invoice in no time. And if you’re unsure, there’s always an accountant ready to help you out.

E-invoicing via Peppol? Smarter, faster, and hassle-free with PIA Go!

Whether you work in construction, plumbing, coaching, or photography, invoicing shouldn’t be a time-consuming task. Peppol makes it easy by automatically sending your invoices to the right place—both to your customers and to the government. With Peppol and PIA Go!, your invoicing becomes not only faster, but also smarter. That way, you have more time to focus on what you do best: your craft.

From Idea to Business: The Essential Checklist for First-Time Sole Proprietors

Starting your own business is an exciting step. You may already have a well-defined project, or you may still be exploring different possibilities. However, the first steps can seem numerous. As a beginner sole proprietor, you want to move forward quickly without getting lost in administrative formalities. This checklist guides you through the essential steps to turn your idea into a real business activity.