iHow it is calculated
Late-payment interest is found from the amount owed, the annual rate and the days overdue:
interest = amount × rate × days ÷ 365
For £10,000 at 11.75% over 90 days: 10,000 × 11.75% × 90 ÷ 365 ≈ £290 interest.
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Legal · Updated 2026
Legal Penalty Interest Calculator
Calculate UK statutory interest on a late commercial payment or a court debt, from the annual rate and the number of days overdue.
Enter your data
£
Enter the amount owed, the interest type and the date range. Each official rate is applied for the exact days it was in force (simple daily interest).
=Interest / penalties
3,206.16£
Amount owed10,000.00 £
Days overdue926 days
Fixed compensation100.00 £
Total to pay13,306.16 £
Period breakdown
| Period | Rate | Days | Interest |
|---|---|---|---|
| 01/01/2024 – 01/07/2024 | 13.25% | 182 | 660.68 £ |
| 01/07/2024 – 01/01/2025 | 13.25% | 184 | 667.95 £ |
| 01/01/2025 – 01/07/2025 | 12.75% | 181 | 632.26 £ |
| 01/07/2025 – 01/01/2026 | 12.25% | 184 | 617.53 £ |
| 01/01/2026 – 01/07/2026 | 11.75% | 181 | 582.67 £ |
| 01/07/2026 – 15/07/2026 | 11.75% | 14 | 45.07 £ |
Statutory late-payment interest is the Bank of England base rate plus 8% (11.75% with the base at 3.75%), fixed for each half-year at the base rate on the preceding 31 Dec / 30 Jun. Court judgment debts carry 8% under the Judgments Act 1838. The rate is applied for each day it was in force across the period. Late commercial payments also carry fixed compensation of £40 / £70 / £100.
10,000.00 £ · 926 days → Interest / penalties 3,206.16 £Indicative legal figures, not advice. Results are estimates — final decisions rest with the court and depend on the specific case. Check the law in force. Instant in-browser calculation, no account.
Last updated: 11 July 2026 Source: GOV.UK — Late payment interest
§ Results are for informational purposes and do not constitute legal advice. For specific situations, consult a lawyer or a notary.
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?Frequently asked questions
What is the statutory interest rate on late payments?
For late commercial (business-to-business) payments the statutory rate is the Bank of England base rate plus 8 percentage points. With the base rate at 3.75% that is 11.75% a year. The rate is fixed at the base rate on the day the debt became overdue.
How is late-payment interest calculated?
Simple daily interest: amount × annual rate ÷ 365, multiplied by the number of days the payment is overdue. For £10,000 at 11.75% over 90 days that is about £290.
What rate applies to a court judgment?
Debts under a court judgment usually carry interest at 8% a year under the Judgments Act 1838, running from the date of judgment until it is paid.
Can I also claim compensation?
Yes. On top of statutory interest, late commercial payments carry fixed compensation of £40 for debts under £1,000, £70 for £1,000–£9,999 and £100 for £10,000 or more.
When can I charge statutory interest?
You can charge it on overdue business-to-business invoices unless the contract sets a different substantial remedy. For consumer debts, the rate is usually whatever the contract or a court sets.
From which day does interest run?
From the day after the agreed payment date, or 30 days after delivery or the invoice date where no date was agreed, until the debt is paid in full.
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