An overpayment simply follows from how advances work: you pay up front, and the amount is calculated from a year you haven't had yet.
Where the overpayment comes from
Health insurance advances are calculated from last year's profit. In the first year there is no last year, so you pay the minimum — and if the year turns out weaker than expected, the advances add up to more than the final liability. Pension-insurance advances are not paid in the first two years by anyone who was not self-employed in the previous five years (outside the flat-tax regime); their premium is simply settled after the annual overview is filed.
The second part is expenses. Under the standard regime, fuel, tolls, rent and insurance all reduce the base. If the records were kept carefully, the final base comes out lower than it looked mid-year. Which costs actually count is worked through in Which costs actually reduce the tax base.
How to claim it
Nothing comes back on its own. A tax overpayment has to be applied for — with the return or later, within six years of the end of the year it arose (§ 155 and § 160a daňového řádu). It is a separate step, and the one most often forgotten. The tax office refunds the money within 30 days of the request, to the account named on it.
The deadline for the return itself is statutory and counted in months from the end of the tax period, not fixed to a date:
| How you file | Deadline (§ 136 daňového řádu) |
|---|---|
| Basic deadline | 3 months after the end of the tax period |
| Electronically, having not filed within 3 months | 4 months after the end of the tax period |
| Filed by a tax adviser, or accounts must be audited | 6 months after the end of the tax period |
Source: zákon č. 280/2009 Sb., § 136.
The insurers work the same way: statements follow the return, and where advances exceeded the calculation the difference is either refunded or credited against future payments.
The 2026 overpayment you have to ask for
2026 produced a second overpayment for drivers on a main activity, which you can get back sooner by application under zákon č. 90/2026 Sb., and which otherwise only shows up in the annual settlement after the overview. Zákon č. 90/2026 Sb. cut the minimum assessment base from 40 % to 35 % of the average wage, so the minimum pension insurance advance is 5 005 Kč a month.
The load-bearing word is from. The cut is not retroactive: for January to June 2026 the advances follow the old wording, at a minimum of 5 720 Kč a month. The difference over those six months (roughly 4 290 Kč) is refunded by the regional social security administration under Čl. II of zákon č. 90/2026 Sb. only on a written request, filed by 31 December 2026.
Sources: ČSSZ — Zálohy na pojistné na důchodové pojištění and zákon č. 90/2026 Sb., Čl. II — “…a to pokud tuto žádost podá písemnou formou do 31. prosince 2026.”
How the advances are built overall is in Insurance advances: how much and when to pay.
What not to do
Do not wait to be told. Nobody will tell you: the system assumes the payer applies. A tax overpayment lapses only six years after the end of the year it arose. For the social advance covering the first half of 2026, 31 December 2026 is the deadline for the quick refund only: if you do not apply you do not lose the difference — it shows up in the annual settlement after you file the overview.
And do not plan the first year around the refund arriving. It comes after the return, not in the month you need it.
Who does this here
Cost records and conversion at the ČNB rate are kept as part of the rental, so the material for the return will be together. The return itself is filed by an accountant — we are not accountants and do not give tax advice, but we will put you in touch with the ones our drivers use.
How the payments themselves work is on Trade licence in Czechia.
