As a sole proprietor, you want to focus on what you really enjoy doing: running your business. However, good planning of your administration is worth its weight in gold. Nothing is more annoying than an unexpected fine from the tax authorities because you missed a date.
To help you keep track, we have listed the most important tax deadlines for 2026 in a summary. Grab your diary and make a note of them right away!
1. VAT declarations(quarterly)
Are you subject to VAT and do you file quarterly declarations? Then these are the four dates you need to mark in your diary. Don’t forget that VAT must not only be declared, but also paid by these dates.
- 26 January 2026: Deadline for VAT declaration for Quarter 4 (from 2025)
- 25 April 2026: Deadline for VAT declaration for Quarter 1
- 25 July 2026: Deadline for VAT declaration for Quarter 2
- 25 October 2026: Deadline for VAT declaration for Quarter 3
Tip from Dexxter: Don’t wait until the very last day. By uploading your invoices throughout the quarter, filing your return at the end of the quarter is just a click of a button.
2. Yearly customer list
The customer list is a list of all your Belgian customers with a vAT number to whom you have invoiced more than €250 (excl. VAT) in the previous year. Even if you did not have any such customers (a “nil listing”), you often have to confirm this.
Deadline: 30 March 2026
3. Tax return (Personal income tax)
This is the “big” tax return in which you declare all your income for 2025. For self-employed persons who are sole proprietors (who often declare specific income via the “Part II” section in Tax-on-web), the deadline is usually in the autumn.
Date: 16 October 2026
This is the date for online submission via Tax-on-web. Please note: do you still have a paper return? Then the date is usually much earlier (often as early as June). However, we always recommend the digital route.
It is also wise to do advance payments, so you don’t face any surprises. There is one date per quarter for this. For the 2027 tax year (i.e. for income from 2026), the Belgian tax authorities have not yet published an official document with specific deadlines for advance payments.
These are the probable dates:
- 10 April 2026 (first advance payment)
- 10 July 2026 (second advance payment)
- 10 October 2026 (third advance payment)
- 20–22 December 2026 (fourth advance payment)
Add these deadlines to your calendar
It is extremely useful to add important deadlines directly to your calendar so that you don’t forget anything. Below are two super easy ways to do this: you can use an iCal link, which you can import directly into almost any digital calendar, or select a Google Calendar link, which allows you to add all important dates to your Google Calendar with a single click.
Simply click on the URL that suits your preference and confirm that you want to add the calendar. This will give you automatic reminders and a summary, perfect for staying well prepared for all tax deadlines.
Never miss a deadline again?
Dexxter users can be absolutely sure that they won’t forget anything. We send timely emails for each deadline so that everything is 100% okay. Submitting VAT declarations, customers and IC listings is very easy with Dexxter and requires hardly any time, effort or knowledge. Good luck!
