Tax return for sole proprietors: what you need to know

Personal income tax: what is it?

Personal income tax applies to the income you earned during the previous year.

For a sole proprietorship, professional income is calculated as your turnover minus your professional expenses and social contributions. The result is your taxable profit.

The tax authorities take all your income into account, including:

• the profit from your sole proprietorship
• any salary from another activity
• certain benefits or pensions and possible rental income

Tax is then calculated on the total of these incomes, taking into account applicable deductions and tax reductions.

What is the difference compared to an employee?

The system differs significantly from that of an employee.

For employees, tax is largely withheld at source through payroll withholding tax. The necessary information is already provided to the tax authorities, which is why the tax return is often pre-filled.

For self-employed professionals, the situation is different. No tax is withheld at source. The entrepreneur must declare their income themselves or rely on an accountant.

Accounting therefore plays a central role. It allows you to track your turnover, expenses, and social contributions. This information forms the basis of your tax return.

PIA Go! automatically gathers this data so you always have a clear overview of your situation.

This is how the tax authorities calculate your taxes

In Belgium, personal income tax is based on progressive rates: the higher your income, the higher the percentage you pay. For the 2024 income year, the tax brackets are as follows:

On top of this tax, you also have to pay municipal taxes (also via your tax return). These can vary from 0% to 9% depending on the municipality where you are domiciled (on 1 January of the year following the income year – for the 2024 tax return, this is 1 January 2025).

All these percentages may seem high, but being self-employed has a major advantage: you can deduct expenses. And this significantly reduces your taxable income.

What expenses can you deduct?

Everything you need to carry out your profession can be recorded as an expense. Think of:

• your laptop, smartphone, printer or software,

• office or work equipment,

• transport costs and fuel,

• rent of your office or part of your home,

• training or seminars,

• insurance, accounting costs, and so on.

Even small purchases can be included, as long as they are business-related. Keeping a well-organised overview can therefore save you hundreds of euros per year.

💡 Tip: with the PIA Go! app, you can scan or upload your receipts immediately. If you choose the Comfort (Max) subscription plan, your accountant will review and process everything, ensuring that you don’t miss any deductible expenses.

When do you need to submit your tax return?

The tax return is submitted via MyMinfin, the online portal of the FPS Finance.
The deadlines are set by law and are as follows:

• A standard tax return submitted by yourself or your accountant: 15 July.

• A tax return with “specific income” submitted by yourself or your accountant: 16 October (extended to 31 October in 2025).

What the term “specific income” includes is determined by the tax authorities. More information can be found here.

💡 Tip: No worries! If you are self-employed, you automatically have the right to submit your tax return by the 16 October deadline (31 October in 2025).

If you miss the deadline, you risk a fine or an “official assessment”. In that case, the tax authorities estimate your income themselves, which is usually not in your favour. They do not take your deductible professional expenses into account.

What happens after your tax return?

After submitting your return, you will receive a tax assessment notice. This document shows how much tax you need to pay or will be refunded.

• If you have paid too little in advance, you will have to make an additional payment.

• If you have paid too much, you will receive a refund.

You can also make advance payments throughout the year. This helps you avoid tax increases and may even give you a small discount (only during the first three years of starting as a self-employed person in a main activity).

Common mistakes among self-employed professionals

1

1. Mixing private and professional expenses

2

2. Forgetting to include social contributions

3

3. Submitting too late

4

4. Not making use of deductible expenses

5

5. Not seeking guidance and therefore missing optimisation opportunities

At PIA Go!, we ensure this does not happen: we monitor your file, provide advice, and submit your tax return correctly and on time.

PIA Go! makes your tax return simple

With PIA Go!, you combine the best of both worlds: digital simplicity and personal guidance. You stay in control, your accountant takes care of the rest. Depending on the subscription plan you choose, you get:

• a dedicated accountant who knows your file,

• an online platform that automatically tracks your figures,

• and proactive advice to optimise your situation intelligently.

We ensure that your tax return is accurate, complete, and submitted on time. All you need to do is confirm, and you can continue working with peace of mind.

Ready to have your finances in order without stress? With PIA Go!, your accounting becomes clear, your tax return simple, and your mind at ease again. Don’t hesitate to contact us — we’re happy to help.