Late payment interest calculator and reminder wording
Worked out in your browser: how much statutory interest and fixed recovery cost a late UK business invoice can attract, and a polite-to-final reminder message you can copy. Nothing you type leaves this page.
Today by default, or the date you expect to be paid.
Check the current rate at bankofengland.co.uk. The default may be out of date.
To keep track of every unpaid invoice, see who to chase each morning and log what clients promise, open Chasebook.
How the interest is worked out
- The rule: under the Late Payment of Commercial Debts (Interest) Act 1998, a business that is paid late by another business can claim interest at 8% a year over the Bank of England base rate, unless the contract sets a different rate. The government guidance is at gov.uk.
- The sum: invoice amount multiplied by that yearly rate, multiplied by the number of days late, divided by 365. This tool does simple interest and rounds to the penny.
- Fixed recovery costs: GBP 40 for a debt under GBP 1,000, GBP 70 from GBP 1,000 to GBP 9,999.99, and GBP 100 for GBP 10,000 or more, per gov.uk (checked 10 October 2026).
Check before you rely on it
The base rate used for a claim depends on the date the debt became due, and the Bank of England changes it several times a year. Enter the rate you have confirmed. This applies to business-to-business debts in the UK. It does not apply to consumers, and a contract may set its own rate. This tool is not legal advice. If a large sum is at stake, speak to a solicitor or a debt-recovery adviser.