OSVČ overpayment calculator from the 2026 cut
From 1 July 2026, minimum social-security advances and the flat-rate tax drop — retroactively from January. Work out the overpayment a Czech freelancer (OSVČ) has built up and how much to pay in July.
Enter your details
Your overpayment
4 932 CZK
for the selected period at the old rate
Old monthly
9 984 CZK
New monthly
9 162 CZK
Saving / month
822 CZK
In July pay only 4 230 CZK instead of 9 162 CZK — the accrued overpayment is offset.
Why the overpayment arises
Act No. 90/2026 Coll.
The amendment lowers the minimum assessment base for a Czech freelancer (OSVČ) from 40% to 35% of the average wage. That reduces both the minimum social-security advances and the band-1 flat-rate tax.
Effective 1 July 2026, retroactive to January
The cut takes effect in July 2026 but applies retroactively for the whole of 2026. So from January to June you paid at the old, higher rate and built up an overpayment.
How to use the overpayment
For the flat-rate tax you can usually just reduce the July payment once by the accrued overpayment. For ordinary social-security advances, ČSSZ refunds it or offsets it against future periods.
Indicative calculation based on 2026 parameters. It does not replace confirmation from ČSSZ or the tax authority.
What you need to know
How much do the advances and flat-rate tax drop?+
The minimum social-security advance (main activity) falls from 5,720 CZK to 5,005 CZK per month — 715 CZK less. The band-1 flat-rate tax falls from 9,984 CZK to 9,162 CZK per month — 822 CZK less.
For how long an overpayment do I have?+
The reduction applies retroactively from January 2026. If you paid at the old rate through June (or into July), you overpaid for those months. Pick the number of such months (1–7) in the calculator.
Do I have to apply for the refund?+
For the flat-rate tax you can usually just reduce the July payment once. For ordinary social-security advances, ČSSZ refunds the overpayment on request or automatically offsets it against future advances.
Does it also cover health insurance?+
This calculator covers the overpayment from the reduction of minimum social-security advances and the flat-rate tax. Health-insurance parameters are governed separately — check the current amount with your health insurer.
Does it apply to secondary activity too?+
The calculation is based on the minimum advances for main activity and band 1 of the flat-rate tax. For secondary activity or higher bands the amounts differ — in Taxorio you always see the correct figure for your case.
Track your advances automatically
Taxorio calculates the correct advances and flat-rate tax and reminds you of payment deadlines. No overpayments, no missed payments.
Try Taxorio for free →