Dutch tax deadlines 2026: the complete calendar for expat ZZP'ers
Every quarterly btw date, the annual income tax window, the late-filing fine, and the optional prepayment that smooths the year, on one page.
A first year as a ZZP'er runs on two calendars at once. One repeats every three months for the quarterly VAT return, and one lands once a year for income tax. Miss either, and the consequence has the same shape: a fine first, then interest on whatever was still owed.
Quarterly filing covers nearly every ZZP'er in the first years, and the four dates never move: the quarter ending in March is due 30 April, the quarter ending in June is due 31 July, the quarter ending in September is due 31 October, and the quarter ending in December is due 31 January 2027. Filing and paying share the same date each time: a return sent on time with payment still in transit is only half finished.
Why the dates never move
The rule behind all four is the same: one month after the quarter closes, no grace period built in, and no reminder beyond the letter the Belastingdienst sends at registration. Freelancers who mark the four dates on a calendar the day they register rarely miss one. Freelancers who plan to remember usually miss one, at least in year one. It does not matter when your first quarter started: the return still covers whatever you invoiced from your KVK registration date onward, even if that was only a few weeks before the quarter closed.
Income tax: the other deadline
The annual income tax return opens on 1 March and is due by 1 May: a two-month window, not a single morning, so most freelancers who already have their numbers from Kwartaal finish weeks before the deadline rather than on it.
Miss a filing, meet the verzuimboete
File the btw return late, even a correct one with nothing owed, and the Belastingdienst issues a verzuimboete starting at €68 for a first late filing. It climbs for repeat lateness, and paying late is a separate, percentage-based fine calculated on the amount owed: a return filed on time but left unpaid is not actually finished.
Smoothing the year: the voorlopige aanslag
None of the above is compulsory smoothing. A freelancer who would rather not meet the annual bill as one spring lump sum can request a voorlopige aanslag: monthly prepayments settled against the final assessment in May. It changes the rhythm of paying, not the total owed, and it stays entirely optional.
Kwartaal keeps the calendar
Every date above is fixed by the calendar, not by whatever app someone uses to track it, but a missed reminder is still the single most common way a first-year ZZP'er meets the verzuimboete. A phone calendar entry works, provided it survives a rebooked holiday or a busy month with a client deadline of its own.
Kwartaal tracks each of these dates against your own registration and legal form, and reminds you with enough runway to act, not just enough to notice you are already late. Kwartaal guides you through this automatically.