Two ways your pay is taxed
Without a signed declaration, srážková daň (withholding tax) of 15 % is deducted from your pay (§ 36 of the Income Tax Act). It is a final deduction — the money goes to the tax authority and you will see it on your výplatnice (payslip) as a "srážková daň" line.
With a signed prohlášení poplatníka, zálohová daň (advance tax) is calculated instead. The rate is the same 15 %, but each month the taxpayer credit of 2 570 Kč is subtracted from the calculated tax. For typical part-time pay the tax therefore comes out at zero and you receive the full gross amount.
Srážková daň
without a declaration
- 15 % is always deducted from your pay
- No credits are applied
- The tax is final — nothing more to deal with
- The deducted tax can be recovered in a tax return
Zálohová daň with a declaration
signed "pink form"
- Rate 15 %, but with a monthly credit of 2 570 Kč
- For ordinary pay the tax works out at 0 Kč
- You may only have the declaration signed with one employer at a time
- You sign it online directly in FixIt (BankID)
The same pay, two outcomes
Here is what a month with pay of 10 000 Kč looks like — below the 12 000 Kč threshold, so no social or health insurance is paid and the only difference is the tax.
- Gross pay
- 10 000 Kč
- Srážková daň 15 % (without a declaration)
- −1 500 Kč
- Net without a declaration
- 8 500 Kč
- Tax with a declaration (after the 2 570 Kč credit)
- 0 Kč
- Net with a declaration
- 10 000 Kč
The taxpayer credit is applied only up to the amount of the calculated tax — any "unused" remainder is neither carried over nor paid out.
Why a declaration usually pays off
As long as 15 % of your monthly pay is lower than 2 570 Kč, the tax with a declaration is zero. But you may only have the declaration signed with one employer — if you already have it elsewhere (for example in your main job), you stay on srážková daň with FixIt.
Further credits and allowances
In the declaration, alongside the basic taxpayer credit you can also claim the tax allowance for children (1 267 Kč per month for the first child, 1 860 Kč for the second and 2 320 Kč for the third and further children) and credits for disability or a ZTP/P card. The declaration guide in FixIt walks you through them and you upload the supporting documents right in the app.
You can get the withheld tax back
Srážková daň is only final until you file a tax return. If you file one for the year 2026, you can include income taxed by withholding in the return, claim credits retroactively, and the tax authority refunds the overpayment.
For that you will need a potvrzení o zdanitelných příjmech (statement of taxable income) — you will find it in the Documents section of your account, no request needed.
FAQ
- Can I sign the declaration if I have my main employment elsewhere?
- Only if you do not have it signed with a second employer. The declaration may be signed with just one payer in the same period. Most people have it signed in their main job — in that case srážková daň stays in place with FixIt.
- When and how can I sign the declaration?
- Any time in your FixIt account — the guide has three steps (credits, documents, signature via BankID). It applies from the month in which you sign it.
- What if I earn nothing in some month?
- Nothing happens. Tax is calculated only from paid-out pay; in a month with no pay nothing is deducted and the credit simply "lapses" — it is not carried anywhere.
Note
This overview is informational and describes how FixIt processes pay under the legislation in effect for the year 2026. It is not tax advice — if you are unsure about your situation, consult a tax advisor.