Late Payment Penalty & Interest Calculator

Free calculator for penalties and interest on late payments. Use a contractual rate (per day or per year), or Russia's Article 395 mode that automatically applies the Central Bank key rate for each period of delay. It splits the calculation across every rate change, handles partial payments, debt increases and the 2022 moratorium — useful for invoices, demand letters and claims.

How to calculate a late-payment penalty

1
Enter the debt amount

Type the outstanding sum and pick a currency if needed.

2
Set the overdue period

Start = the day after the due date; end = the day of actual payment.

3
Choose a mode

Article 395 (rate fills in automatically), a contractual penalty, or a statutory fraction of the key rate.

4
Add events and moratorium

Enter partial payments and debt increases, and apply the 2022 moratorium if relevant.

5
Copy the calculation

Get a period table, total and amount in words — for an invoice, demand letter or claim.

Calculate statutory or contractual interest on overdue debts, split period by period

Day after the payment due date
Through the day of actual payment
Manual rate, partial payments & moratorium
% from
Applies if the debt arose before 01.04.2022 (Russia, Decree №497).
Interest (penalty) amount
—
Remaining debt
—
Days overdue
—
Debt + interest
—
Period Days Debt Rate Formula Interest
Total interest—
This calculator provides an informational estimate and is not legal advice. Rates change over time — verify the period and total before relying on it in a claim or court.

What the calculator does

Automatic rate by period
In Article 395 mode it applies the Bank of Russia key rate for each day of delay and recalculates at every rate change — the full rate history is built in.
Court-ready breakdown
A sub-period table with dates, days, rate, formula and accrued amount — ready to attach to a claim or demand letter.
Actual day count 365/366
Calendar days of delay, with the annual rate divided by the real number of days in the year.
Moratorium & partial payments
Excludes the 01.04–01.10.2022 moratorium window and recomputes the balance after each payment or debt increase.
Three modes in one
Article 395 interest, a contractual penalty (% per day or per year) and statutory penalties (1/300, 1/150, 1/130 of the key rate).
Total in figures and words
Shows the result in figures and, for rubles, spelled out in words — ready to paste into a document.

Why this calculator is more accurate

Most online calculators apply a single rate to the whole period. This one splits the delay into sub-periods at every key-rate change and year boundary, switches the 365/366 divisor correctly, excludes the moratorium and recomputes the balance after partial payments — producing a result suitable for a claim rather than a rough estimate.

Frequently asked questions

How is interest under Article 395 calculated?

Since 1 August 2016 interest accrues at the Bank of Russia key rate in force during each period. Calendar days of delay are used, and the annual rate is divided by the actual number of days in the year (365 or 366). If the rate changed during the period, the calculation is automatically split into sub-periods.

What is the 2022 moratorium?

From 1 April to 1 October 2022 a moratorium was in force (Russia, Government Decree №497): for obligations that arose before 01.04.2022, financial penalties — including Article 395 interest — do not accrue for that window. Enable the option if the debt arose before the moratorium began.

Is the payment day included?

By default yes: interest accrues through the day of payment (Supreme Court Plenum №7, para. 48). Untick "Include the payment day" if your calculation should stop the day before.

How does the statutory 1/300 penalty differ?

Many laws (the Russian Tax Code, Housing Code, Law No. 214-FZ on shared construction) compute the penalty as a fraction of the key rate per day — 1/300, 1/150 or 1/130 — a daily rate, with no division by days in the year. The order differs by type: for companies, the Tax Code's "1/150 from day 31" rule has been temporarily suspended since 2022 (in 2022–2024 a flat 1/300 for the whole term; in 2025–2026 — 1/300, then 1/150 on days 31–90 and 1/300 again from day 91), while utilities penalties for individuals follow a 0 / 1/300 / 1/130 grid. Pick the penalty type and the calculator applies the correct formula.

Can I attach the calculation to a claim?

Yes. "Copy calculation" produces a period-by-period table with the total and (for rubles) the amount in words, ready to paste. Note that this is an informational tool, not legal advice — verify the dates and total before filing.

Which key rate is used and how current is it?

The official Bank of Russia key-rate history with effective dates is built in. The rate changes by decisions of the CB Board; the code notes the last verification date. For absolute precision in court, confirm the latest value at cbr.ru.

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Who is this tool for?
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