The Three Bills That Blindsided Me as a Belgian Freelancer

A while back I wrote about the six financial realities of going freelance in Belgium. I covered the concepts every new freelancer needs: social contributions, sick pay, taxes, the whole picture. The feedback I got most was some version of “I knew about this, but I still wasn’t ready for it.”

That got me thinking… Knowing those things are coming your way is one thing, actually living through them is another thing entirely. So, this post is the follow-up: not the theory, but reality. The actual bills, what they looked like, what they felt like, and what the numbers meant when they arrived, for me.

Bill 1: The INASTI Catch-Up

This one takes a few years to arrive, which almost makes it worse.

When you start as a freelancer in Belgium, your social contributions are based on a provisional minimum. In your first year, that is around €900 per quarter, give or take depending on your social insurance fund. For most people coming from employment, this feels almost reasonable. You pay it, you move on, you assume that is roughly what it costs.

Then, about two to three years in, the letter arrives.

The government now knows what you actually earned in those first years. And if you were billing IT rates and working full-time, you were almost certainly earning well above the provisional minimum threshold. So, they work backwards, calculate what you should have paid, subtract what you did pay, and send you the difference. All at once. In one nice (environmental-friendly) letter.

For a typical IT freelancer in Belgium billing somewhere between €600 and €900 per day, that catch-up bill can land anywhere between €5,000 and €15,000 depending on your rate, your volume, and how long the provisional period ran. In theory you should have seen this coming, but as you are going through live and your new situation, you don’t really think about it until the shock arrives in an envelope. Even though you paid your contributions on time every quarter, you still owe five figures “out of nowhere”.

How can you soften the blow? Set aside 20 to 22% of every invoice into a separate account and do not touch it. EVER. When the recalculation arrives, you want that money sitting there waiting for that moment.

Bill 2: The Month You Get Sick

This one is not really a literal bill or tax. It’s something you don’t have anymore but that you only notice when you need it. when you realise the money you were expecting is not coming.

As an employee in Belgium, getting sick is uncomfortable but manageable. Your employer covers you for the first month at full salary. After that your national health provider takes over at a somewhat reasonable amount.

As a freelancer, the statutory sickness benefit from your national health provider is not a soft landing. Fall sick for less than eight days and you get nothing: not reduced, not backdated, nothing. Cross eight days and it pays out retroactively from day one, at a flat rate that has no relationship to what you actually bill. As of March 2026, that is €81.10 a day if you have dependents, €64.27 if you are single, and €49.29 if you are cohabiting, according to RIZIV. If you were billing €700 or €800 a day, that’s a huge gap between what they pay and your real income. THAT’s the painful part.

The moment this hits you in the face is not when you read about it in a blog post. It’s the first time you’re really sick, fever and headache, and the first thought that crosses your mind is not “I should sleep” but “how long can I afford to stay down.” Believe, even if you are a healthy twenty or thirty something, there will be moments like that.

How can you protect yourself against this to a certain extent? Enter, Gewaarborgd inkomen. It’s the private income protection insurance most freelancers layer on top, and it is what people usually mean when they say “the first month is on you.” Most of these GI policies have a waiting period of around 30 days before they start paying, topping up the statutory rate toward something closer to your actual income. The premiums run a few hundred euros a month depending on your age and coverage level, which sounds like a lot until you price out a month living on €64 a day instead of your usual rate. The other piece is a cash buffer: six months of fixed personal expenses in an account you do not touch unless things go properly sideways. Not 1 or 2 months, but Six.

Bill 3: The Tax Bill Timing Gap

Belgium’s tax system for freelancers is not designed to punish you. It is designed for people who understand cash flow, which most people starting out, do not.

Belgium has a system of quarterly advance tax payments called ‘voorafbetalingen‘ (I’ll translate them to prepayments), due in April, July, October and December. You are not legally required to make them. But skip them or underpay, and you get a surcharge on your final bill. The surcharge is not enormous but it is entirely avoidable, which makes paying it at the end of the year feel especially bad. It can be the difference between looking forward to receiving that Government letter somewhere in September and dreading it.

You’d thing the x% surcharge is the trap. But no, it’s simpler: In your first year, invoices go out and money comes in. It feels good. But your tax bill for that year does not arrive until well into the following year, sometimes 18 months after the income that triggered it. For a lot of new freelancers that money has been spent by then. Not recklessly, just spent. On the business normally. On the entirely reasonable assumption that money in your account is money you have. Until you have paid your corporate tax, it’s safer to assume 25% of what comes in, isn’t.

Treat 30 to 35% of every net invoice as not yours. Put it on a business savings account and let it sit there. Pay your prepayments on time every quarter based on your accountant’s estimate. When the final bill arrives, it should feel like a relief.

Why These Bills Still Hit Freelancers Who Know About Them

None of these are trade secrets or there isn’t a rite of passage for new entrepeneurs where this is kept from them. Your accountant will explain all three on day one. And they still hit hard. Every time.

You can know exactly how the recalculation works and still feel the floor shift when you open that envelope and see the number. You can understand that sick pay for freelancers is terrible and still feel completely unprepared the first time you lie in bed doing rough mental calculations about your invoice pipeline. Knowing what is coming does not automatically mean you have arranged your finances to absorb it.

The freelancers who come out of the first few years without a crisis are the ones who treated the numbers as a constraint from day one. They set up the separate accounts before the invoices arrived. They took out the insurance before they needed it. They made the advance payments before the surcharge showed up.

The paperwork is boring. Doing it on a Tuesday morning when everything is fine and nothing is on fire is actually difficult. That is the real hard part: the lack of urgency.

If you have not read the broader overview yet, the Going Freelance in Belgium post covers the full picture of what changed financially after I made the jump. This post is just the three moments I remember most clearly.

The figures in this post are ballpark estimates based on Belgian regulations as of 2025/2026. Your actual contributions, sick pay rates and tax situation will vary based on your income, social insurance fund and company structure. Talk to a Belgian accountant before making any financial decisions.

Sources:

• Statutory sickness benefit amounts for self-employed (2026): RIZIV
• Eligibility rules and the 8-day threshold: RSVZ / INASTI