Glossary
Dutch tax terms, explained in English
Letters from the Dutch tax office use words nobody ever explained to you. Here they are in one place, each with an explanation you can follow without an accountant.
In short
As a business owner in the Netherlands you deal with two institutions: the KvK (Kamer van Koophandel), the Dutch business register where your business is listed, and the Dutch tax office (Belastingdienst), which levies VAT and income tax. The Belastingdienst gives you a VAT identification number (btw-id) for your invoices and a VAT tax number (omzetbelastingnummer) for your contact with the Belastingdienst itself. A voorlopige aanslag is an estimate of your income tax that you can pay monthly; the definitieve aanslag follows after your return. You receive a naheffingsaanslag when, for example, you forgot to file a VAT return. This list explains twenty-nine of these terms, each with its own link.
Institutions and numbers
- Belastingdienstthe Dutch tax office
- The government body that levies and collects taxes, including VAT and income tax. You file your VAT return in Mijn Belastingdienst Zakelijk and your income tax return in Mijn Belastingdienst. Letter from the Belastingdienst
- KvK (Kamer van Koophandel)the Dutch KvK business register
- This is where you register your business. You then get a KvK number of eight digits, which belongs on your invoices, quotes, letters and website. Starting a sole proprietorship
- Eenmanszaaksole proprietorship
- A common legal form for people starting on their own. There is no separate company next to you: the profit is your income, you pay income tax on it, and your private assets are liable for the debts of the business. Bookkeeping yourself or an accountant?
- Btw-identificatienummer (btw-id)your VAT number for customers
- The number for all your contact with customers and suppliers: it goes on your invoices, your letterhead and your website. It looks like NL123456789B01 — NL, nine digits, the letter B and two digits. VAT number and turnover tax number
- Omzetbelastingnummer (ob-nummer)your number at the Dutch tax office
- You use this number only when dealing with the Belastingdienst itself, for example in a letter or on the phone. If you are self-employed (zzp), the first nine digits are your citizen service number (BSN) — so never put it on an invoice. VAT number and turnover tax number
- Machtigingauthorisation to act on your behalf
- With a machtiging someone else, your accountant for instance, may handle your tax matters at the Dutch tax office (Belastingdienst). As a sole trader you arrange it with DigiD Machtigen, with a vof or bv through a chain authorisation (ketenmachtiging) via eHerkenning. You never give your DigiD login details to anyone else. Authorising your accountant
- Beconnummerregistration number of a bookkeeper
- A number by which the Dutch tax office (Belastingdienst) recognises a tax service provider, such as a bookkeeping practice (administratiekantoor) or tax consultant. It is optional and free. It is your bookkeeper's number, not yours: as a business owner you do not apply for one yourself. Starting a bookkeeping practice
VAT
- Btw (omzetbelasting)VAT
- The tax you charge your customer and pay over to the Dutch tax office (Belastingdienst). Omzetbelasting is the official name; in everyday use it is called btw. VAT in the Netherlands
- Btw-aangiftethe VAT return
- The statement of the VAT you charged and paid in a period. The return and the payment must be in by the last day of the month after the period: for the third quarter, that is 31 October at the latest. VAT return
- Voorbelastinginput VAT on your own purchases
- The VAT you paid yourself on business purchases. In your VAT return you deduct it from the VAT you owe, in box 5b. VAT return
- Btw verlegdreverse charge: your customer reports the VAT
- Not you as the supplier, but your customer reports the VAT. Your invoice then shows no VAT amount but the words 'btw verlegd'. In the Netherlands this applies mainly to subcontractors in construction, cleaning and landscaping. Reverse charge (btw verlegd)
- ICP-opgaafEU sales listing
- A separate statement next to your VAT return, in which you report your supplies of goods and services to businesses in other EU countries, per customer with their VAT number. Selling within the EU
- KOR (kleineondernemersregeling)VAT exemption for small turnover
- An exemption for businesses with a turnover of no more than € 20,000 per calendar year. You charge no VAT and in principle file no VAT return, but you also cannot reclaim the VAT on your own purchases. Small businesses scheme
Letters and assessments
- Aangiftebriefinvitation to file a return
- The letter in which the Dutch tax office (Belastingdienst) asks you to file an income tax return. Once you receive it, filing is mandatory; the deadline is in the letter and is often 1 May. Income tax return
- Voorlopige aanslagprovisional income tax assessment
- An estimate of the income tax you will pay or get back, so you can pay or receive it monthly instead of all at once. After your return it is settled against the definitieve aanslag. If the estimate no longer fits, you can have it changed. Voorlopige aanslag (provisional assessment)
- Definitieve aanslagfinal assessment
- The assessment you receive after your income tax return. What you already paid or received through the voorlopige aanslag is settled against it. Letter from the Belastingdienst
- Naheffingsaanslagadditional assessment, usually for VAT
- An assessment you receive when VAT is missing, for example because you forgot to file a VAT return or did not pay it (in full). If you forgot the return, it contains an estimated amount and you still file the return in Mijn Belastingdienst Zakelijk. Letter from the Belastingdienst
- Suppletiecorrection of a VAT return
- The form you use to correct a mistake in an earlier VAT return. If it concerns € 1,000 or less, you include the difference in your next return; if it is more, you file a suppletie, no later than eight weeks after you discovered the mistake. Corrections are possible up to five years after the year concerned.
Income tax
- M-aangiftetax return for the year you moved
- The income tax return for the year in which you came to live in the Netherlands or left it. It covers the whole year, including the months when you did not yet, or no longer, live here. You file it online in Mijn Belastingdienst or on the paper form M, by 1 July of the following year; as a business owner you also fill in the M annual statements (M-jaarstukken).
- Urencriteriumhours criterion: at least 1,225 hours a year
- The requirement to spend at least 1,225 hours per calendar year on your business. If you meet it, you are entitled to the zelfstandigenaftrek and the startersaftrek. The hours criterion
- Zelfstandigenaftrekself-employed deduction
- A fixed amount you deduct from your profit if you meet the hours criterion: € 1,200 in 2026. From state pension (AOW) age it is half. The hours criterion
- Startersaftrekstarter's deduction
- An extra deduction on top of the zelfstandigenaftrek: up to three times in your first five years as a business owner, € 2,123 in 2026. It also requires meeting the hours criterion. The hours criterion
- MKB-winstvrijstellingSME profit exemption
- A part of your profit on which you pay no income tax: 12.7% in 2026, calculated on the profit after the entrepreneur's deductions. You do not need to apply for it; the Dutch tax office (Belastingdienst) takes it into account in your return automatically. Tax breaks for freelancers
- KIA (kleinschaligheidsinvesteringsaftrek)small-scale investment deduction
- An extra deduction on your profit when you invest in business assets in a year. In 2026 it starts at an investment total of € 2,901; an asset costing less than € 450 does not count. Investment deduction (KIA)
Bookkeeping
- Factuureiseninvoice requirements
- The details an invoice to another business must contain, such as your btw-id, your KvK number, a sequential invoice number and the VAT amount per rate. You send the invoice no later than the 15th day of the month after the supply. Invoice requirements
- Creditnotacredit note
- An invoice with a negative amount that reverses an invoice you already sent, in full or in part. You do not change an invoice once sent; you correct it with a credit note.
- Bewaarplichtduty to keep records for seven years
- The obligation to keep your records for seven years: invoices, bank statements, your ledger and contracts. Records about real estate must be kept for ten years. Keeping them digitally is allowed, as long as everything stays readable and verifiable. Keeping records
- Auditfile (XAF)export of your bookkeeping
- A file with the complete journal of a financial year, in a fixed format that the Dutch tax office (Belastingdienst) can read during an audit. From 1 January 2027 the Belastingdienst accepts only XAF 4.0 for submission. Importing an audit file
- RGS (Referentiegrootboekschema)standard Dutch chart of accounts
- A Dutch standard list of ledger accounts, so that a set of books means the same thing in every package and at the accountant. RGS is also meant for official bodies: it ties in with SBR (Standard Business Reporting), the standard for submitting figures to the Dutch Belastingdienst, the KvK, the bank and other official institutions. The chart of accounts in booxx is based on it.
Which letter is which?
For income tax you receive three kinds of letters that look alike: an aangiftebrief (you must file a return), a voorlopige aanslag (an estimate, usually with monthly instalments) and a definitieve aanslag (the final settlement after your return). For VAT you receive a naheffingsaanslag when a return or a payment is missing.
The top of the letter says which kind of assessment it is and which year or period it covers. Together those two tell you what to do — and whether it is an estimate you can still have adjusted, or the final settlement.
Why the terms stay in Dutch
This list also exists in Dutch, Polish, Hungarian and Romanian, and in every language the term itself stays in Dutch. That is deliberate: on your letters, in Mijn Belastingdienst and in conversations with your accountant you meet the Dutch word, not a translation. The explanation is in your own language; the word is the word you will see again.
Updated October 2, 2026. General explanation of the Dutch rules, not tax advice — for your own situation, decide together with your accountant or the Dutch Tax Administration.
Frequently asked questions
What is the difference between the btw-id and the omzetbelastingnummer?
You use the btw-id (NL123456789B01) with customers and suppliers: on your invoices, your letterhead and your website. You use the omzetbelastingnummer only when dealing with the Dutch tax office (Belastingdienst). For a self-employed person the omzetbelastingnummer contains the citizen service number, which is why it does not belong on an invoice.
What should I do with a voorlopige aanslag?
Check whether the estimate matches what you expect to earn this year. If it does, pay the instalments as shown on the assessment. If it does not, you can have it changed; after your return the definitieve aanslag follows, and everything is settled then.
I made a mistake in my VAT return. What now?
If it concerns € 1,000 of VAT or less, include the difference in your next VAT return. If it is more, file a suppletie with the Dutch tax office (Belastingdienst) as soon as possible and no later than eight weeks after you discovered the mistake. Corrections are possible up to five years after the year the mistake relates to.