Late-payment interest 2026
Find out how much extra you owe when an invoice, loan, or rent payment is paid late. This calculator computes statutory default interest under Government Regulation No. 351/2013 Coll. — the CNB repo rate plus 8 percentage points, meaning 11.50% p.a. in H1 and 11.75% p.a. in H2 2026. Just enter the outstanding amount and the number of days late.
How default interest is calculated
Default interest (úrok z prodlení) is a statutory penalty for late payment of a monetary debt. Unless the parties have agreed a different rate in their contract, the rate set by Government Regulation No. 351/2013 Coll. applies: the CNB repo rate valid on the first day of the calendar half-year, plus 8 percentage points. For 2026 this means two different rates depending on when the delay began:
- H1 2026 (January–June): repo rate 3.50% + 8 p.p. = 11.50% p.a.
- H2 2026 (July–December, after the CNB raised the repo rate to 3.75% from 19 June 2026): 11.75% p.a.
Interest is calculated on the principal (the outstanding debt) for each day of delay, using a 365-day year regardless of leap years.
Default interest = outstanding debt × annual rate × days late / 365
Sample calculation, step by step
| Step | Item | Calculation | Amount |
|---|---|---|---|
| 1 | Outstanding debt | principal entered | CZK 10,000 |
| 2 | Rate (H2 2026) | repo 3.75% + 8 p.p. | 11.75% p.a. |
| 3 | Days late | number of days entered | 90 days |
| 4 | Interest calculation | 10,000 × 0.1175 × 90 / 365 | CZK 289.73 → CZK 290 |
| 5 | Total due | 10,000 + 290 | CZK 10,290 |
In this example the daily interest works out to roughly CZK 3 (10,000 × 0.1175 / 365), handy for a quick estimate if the delay keeps growing.
What affects the result
- Date the delay started — determines which half-year, and therefore which rate, applies; the rate stays fixed for the whole delay once it starts within a given half-year.
- Amount of the outstanding debt (principal) — interest is calculated only on the unpaid principal, not on previously accrued interest or fees.
- Number of days late — counted from the day after the due date through the day of payment (inclusive), so exact day counting matters.
- Contractual terms — if the parties agreed a different default interest rate, it takes precedence over the statutory rate (except for consumer protection against grossly disproportionate terms).
When this calculation is useful and what to watch out for
This calculator gives a quick estimate of statutory default interest on invoices, loans, rent, and other monetary obligations between businesses and individuals. It does not include contractual penalties, debt-collection costs, court fees, or interest on interest (generally not permitted under Czech law). If a delay spans both halves of the year, split the calculation into two parts with the respective rates and add the days separately. The result is indicative only — for debt collection or a dispute, verify the figures with a lawyer or accountant.
⚠️ Indicative calculation, rates current for 2026. Not a substitute for an accountant or tax advisor — verify important decisions with the Czech Financial Administration.
FAQ
How is default interest (úrok z prodlení) calculated in 2026?
Default interest is calculated as: outstanding debt × annual rate × number of days late / 365. The annual rate for 2026 is based on the Czech National Bank (CNB) repo rate valid on the first day of the relevant calendar half-year, plus 8 percentage points.
What is the current statutory default interest rate in 2026?
In H1 2026 the rate is 11.50% p.a. (CNB repo rate 3.50% + 8 p.p.). In H2 2026 (from 19 June 2026, when the CNB raised the repo rate to 3.75%), the rate is 11.75% p.a.
Why does the rate differ between the two halves of the year?
Government Regulation No. 351/2013 Coll. ties the statutory default interest rate to the CNB repo rate valid on the first day of each calendar half-year (1 January and 1 July). A mid-period CNB rate change does not affect interest already accruing — what matters is the rate at the start of the half-year in which the delay began.
Does statutory default interest apply between private individuals too?
Yes. The statutory rate under Regulation No. 351/2013 Coll. applies automatically whenever the parties have not agreed a different default interest rate in their contract — it covers debts between individuals, businesses, and consumer relationships alike.
Can parties agree on a different default interest rate by contract?
Yes, for both commercial and civil-law obligations the parties may agree their own rate. If they don't, the statutory rate described above applies automatically. In consumer contracts, an agreed rate must not be grossly disproportionate to the statutory amount.
From when is default interest counted?
Interest runs from the day following the due date until the day the debt is actually paid (inclusive). The calculator uses the number of days falling within this period — enter it as the total whole days of delay.
Does the creditor have to prove actual damage to claim default interest?
No. Default interest is a flat statutory sanction for late payment of a monetary debt, and the creditor does not need to prove any actual damage or harm — the claim arises automatically once the debtor is in default.
Is default interest tax-deductible for the debtor or taxable income for the creditor?
For the debtor it is generally a non-deductible expense (it is punitive in nature); for the creditor, received default interest is taxable income. The exact tax treatment can vary by entity type — consult a tax advisor for your specific situation.
Sources & legislation
📅 Last updated: 16 July 2026