Free tool · no signup
Late payment interest calculator.
Under the Late Payment of Commercial Debts Act, you can charge statutory interest at the Bank of England base rate + 8% on every overdue commercial invoice — plus a fixed compensation fee. Most tradespeople never claim it. Here’s what you’re actually owed.
Current rate: 3.75% (held 30 April 2026). The statutory rate is fixed every 6 months — use the rate that applied when your invoice became overdue. Verify on bankofengland.co.uk.
Fill in the invoice amount, due date, and paid (or today) date to see your calculation.
Tired of chasing payments?
Get it done automatically.
Honest Invoices tracks due dates for you, calculates statutory interest automatically once an invoice is overdue, and sends compliant reminders with a clear paper trail. £15/month, locked. 14-day free trial — no card.
How this is calculated
- Base rate as of 30 April 2026: 3.75% (held at the MPC meeting on 30 April 2026 — verify on bankofengland.co.uk). Use the rate that applied when your invoice became overdue.
- Statutory interest = invoice amount × (base rate + 8%) × days overdue ÷ 365 (simple interest).
- Fixed compensation fee: £40 (debts < £1,000), £70 (£1,000–£9,999), £100 (£10,000+).
- Applies to business-to-business commercial debts only — not consumer invoices.
- Authority: GOV.UK — late commercial payments and the Late Payment of Commercial Debts (Interest) Act 1998.
- This is a guide, not legal advice. If a client disputes the charge, take legal advice before pursuing further.