What does your late-paying customer owe you?
UK law lets a business add 11.75% a year interest and a fixed £40 to £100 to any B2B invoice paid late. Enter the invoice and see the figure. No sign-up.
You can add to this invoice
£106.22
- 45 days late (due 2026-08-28)
- £36.22 interest at 11.75% a year (8% + 3.75% Bank Rate), about £0.80 a day
- £70 fixed recovery costs, claimable once per invoice
Reminders go out on your schedule, in your tone. The interest figure sits next to each late invoice so you decide if and when to raise it.
The rules this uses
- Interest: 8% + Bank Rate (3.75% since 2026-09-17), simple, counted daily from the day after payment was due.
- No agreed date: payment is late 30 days after the invoice or delivery.
- Fixed recovery costs: £40 under £1,000 · £70 to £9,999.99 · £100 from £10,000.
- Business customers only. Not available where your contract already sets an interest rate. Not legal advice.
Sources, checked 2026-10-10: gov.uk late commercial payments · Bank of England Bank Rate
Questions
What interest can I charge on a late invoice in the UK?
Statutory interest is 8% plus the Bank of England base rate, currently 3.75%, so 11.75% a year. It applies to business-to-business debts and only if your contract doesn't set its own rate.
When does an invoice become late?
On the agreed date. If none was agreed, 30 days after the customer received the invoice or you delivered the goods or service, whichever is later.
What are the fixed recovery costs?
£40 for debts under £1,000, £70 from £1,000 to £9,999.99, and £100 for £10,000 or more. You can claim them once per invoice, plus reasonable further recovery costs.
How do I add the interest?
Gov.uk says to send a new invoice for the interest and costs. Many businesses mention the figure in a firm reminder first; most customers pay before it's raised.