Small errors tend to surface at the worst moment: a btw return, an income tax filing, or a tax audit. Below are five mistakes we see most often, with Dutch-specific fixes.
1. Mixing private and business money
Paying for a laptop with a private card or buying groceries from the business account makes your records hard to trust.
- Eenmanszaak or ZZP: a separate business account is not legally required, but it is strongly advisable. Your business and private assets are legally the same, so mixing is easy, and tax treatment of private use gets complicated.
- BV: the company is a separate legal entity, so a separate account is effectively essential. Money you take out must be recorded properly, for example, as a salary, dividend, or a loan (rekening-courant), and not as an unexplained withdrawal.
2. Losing receipts and small expenses
Parking, subscriptions, train tickets and supplies add up. If you can’t prove them, you risk losing the deduction, and for btw, the input tax you could have reclaimed. Dutch rules require you to keep your records and supporting documents for 7 years. For some real estate-related btw records, the period is longer. Digital copies are generally accepted when they are complete and readable, but confirm the details on belastingdienst.nl.
3. Leaving bookkeeping until the deadline
Doing everything on the last day before the btw deadline leads to forgotten invoices, wrong categories and rushed returns.
A simple routine:
- Weekly (15 minutes): book new transactions, upload receipts, check which invoices are unpaid.
- Monthly: reconcile the bank, review your profit and loss, and chase late payers.
- Quarterly: prepare your btw return a few days before the deadline, not on it.
4. Getting btw (VAT) wrong
Btw, errors are the most expensive mistake because they affect what you pay and what you can reclaim. Common problems:
- Invoices missing legal details, such as your btw number, KVK number, a sequential invoice number, the date, the btw rate and the btw amount. An incomplete invoice can put the deduction at risk.
- Wrong rate or wrong category. The standard rate is 21% and the reduced rate is 9%, and some supplies are exempt or zero-rated.
- Misunderstanding the KOR. The kleineondernemersregeling is a btw exemption for businesses with annual turnover up to €20,000. If you use it, you don’t charge btw, don’t file btw returns, and can’t reclaim btw on your costs. Since 2025 the turnover limit has to be respected in both the current and the previous calendar year. If your turnover passes €20,000, you must charge btw again from that point. The KOR only affects btw, not your income tax or your duty to keep records.
- Missing the deadline. Most small businesses file quarterly. The return and payment are generally due by the end of the month after the quarter (for example, the Q3 return by 31 October). Check your own filing period in your Belastingdienst account.
Worked example (quarterly return):
| Excl. btw | Btw (21%) | |
|---|---|---|
| Sales invoices | €10,000 | €2,100 |
| Business purchases | €4,000 | €840 |
| Btw to pay | €1,260 |
If one €840 invoice is missing or wrong, you either overpay or end up correcting your return later.
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5. Never looking at your reports
Bookkeeping isn’t just compliance. A business can be profitable on paper and still run out of cash because customers pay late.
Review monthly:
- Revenue and expenses compared with the previous month
- Cash position and upcoming payments (including the btw you owe)
- Unpaid invoices and their age
- Profit and loss
A common trap is spending money that is actually owed to the Belastingdienst. Set the btw aside in a separate savings account as you invoice.
FAQ
How long must I keep my business records in the Netherlands?
Generally 7 years, with longer periods for some real estate-related btw records.
Do I have to file a btw return if I use the KOR?
No. You also can’t charge btw or reclaim btw on costs. The KOR doesn’t change your income tax obligations.
Can I leave the KOR whenever I want?
Under the rules in force since 2025/2026 you can generally opt out at any time, but confirm the current conditions with the Belastingdienst.
Do I need an accountant?
Not always, but it is worth asking one when you choose between the KOR and the normal regime, start a BV, or hire staff.