Calculators and tools · 3 min read

Flat-Rate Tax Calculator — Is It Worth It?

Compare flat-rate tax with the standard tax regime. The calculator shows which option saves you more — for all 3 bands in 2026.

What the calculator compares

The calculator shows whether the flat-rate tax regime or the standard regime with flat-rate expenses works out better for you. You can optionally add a comparison with actual expenses as well.

The result shows the total annual payments (tax + social + health insurance) for each regime and highlights in colour which option saves you more — in CZK per year and per month.

💡 Open the calculator: taxorio.cz/en/tools/flat-rate-tax-calculator

How to use the calculator

  1. Enter your annual income — total invoiced business income for the year (excluding VAT).
  2. Choose the expense flat rate for your field:
    • 80% — craft trades, agriculture.
    • 60% — other trades (the most common).
    • 40% — other self-employed activity (liberal professions).
    • 30% — rental.
  3. Optionally tick I have actual expenses (for comparison) and enter their amount — the calculator adds a third comparison card.
  4. Set the number of dependent children. The child tax allowance can only be claimed in the standard regime — for families with children, this often decides more than the rates themselves.

How to read the results

The calculator shows up to three cards:

  • Flat-rate tax — total annual payments under the flat-rate regime, automatically placed in the correct band (1, 2 or 3).
  • Standard regime (flat-rate expenses) — payments under standard taxation with the expense flat rate at your chosen percentage.
  • Standard regime (actual expenses) — shown only if you entered actual expenses.

Checking eligibility

Below the expenses is a block called Flat-rate tax eligibility. These aren't just reminders — two of them are toggles that tell the calculator where you stand, and it then either calculates the result accordingly or shows Flat-rate tax is not available along with the reason:

  • Annual income up to CZK 2,000,000 — the calculator warns as soon as the entered income goes over the limit.
  • I am a VAT (DPH) payer — VAT payers cannot enter the flat-rate tax regime.
  • I have employment income — except for income taxed by withholding tax (for a DPP contract, that means income that doesn't reach the threshold amount of CZK 12,000 a month for 2026; in 2025 it was CZK 11,500).

Further down the page you'll also find conditions the calculator doesn't ask about, because it can't tell them from numbers alone — for example, that you must not be a debtor in insolvency proceedings.

⚠️ Watch out for credits and deductions: Under the flat-rate regime, tax is paid as a flat amount, so you can't claim any tax credits (for children, a spouse, or disability), nor the non-taxable parts of the tax base under § 15 of the Income Tax Act (mortgage interest, pension and life insurance, donations). If you rely on these, the standard regime can work out better despite its higher headline payments.

What to do after the calculation

  • If flat-rate tax works out in your favour, file the entry notice by 10 January of that year with your tax office (by data box or through Moje daně).
  • In Taxorio, then go to Settings → Tax regime and switch to flat-rate tax — Taxorio will adjust the Overview cards and the tax calendar for you.