Free tool

Statutory interest calculator for late paymentCheck interest on an unpaid debt

Check how much interest has accrued on your unpaid invoice or other receivable. Free, no account or registration required. To recover interest together with the principal, submit your case online.Enter the debt amount and payment due date. We calculate late payment interest from the following day. Select the type of interest. The calculator is free and requires no account.

Interest calculator

Check the estimated interest on an invoice or loan as at the calculation date.

Debt amount

Payment due date

Interest type

Rates verified on 25.09.2026: Civil Code interest according to ZUS, commercial interest according to M.P. 2026, item 642.

Or enter a custom annual rate % (optional, overrides the type)

Result based on the rates applicable in each period.

Example calculation for 10 000 zł

Estimated total interest as at 2026-10-23

76,03 zł

30 dni late · 9.25% per year

Daily increase

+ 2,53 zł

at the current rate

Weekly increase

+ 17,74 zł

7 days

Monthly increase

+ 76,03 zł

~30 days

Principal amount: 10 000,00 PLN. 30 dni from the payment deadline. Stawka: 9.25% per year. Indicative calculation (estimate) — not legal advice. The final interest amount depends on the circumstances of the case and the applicable rates.

How B2B debt recovery works

The result is illustrative; the precise calculation depends on rate changes during the delay and the type of claim.The result is an estimate. The exact amount depends on the type of debt and changes in interest rates over time. The result alone does not establish that you are entitled to that amount. See also transparent commission ranges or see how we recover business debts.

See how we could handle your case.

A short consultation is free and carries no obligation. Tell us what happened and we will make an initial assessment of your prospects and explain possible outcomes and next steps.

Learn about the next steps

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