Chase an unpaid invoice
When another business doesn't pay you on time, you're entitled to more than the invoice. The law lets you charge interest and a fixed sum on top — and most people never claim either.
Fill this in and it works out what you're owed, then writes the letter.
If you agreed no date, the law says 30 days after they got the invoice.
The Act adds 8% to this. The rate is fixed twice a year — the base rate on 30 June applies to debts falling due July to December, and the rate on 31 December applies to January to June.
They owe you
£1,584.49
30 days overdue at 11.75%
- Invoice
- £1,500.00
- Statutory interest
- £14.49
- Fixed compensation
- £70.00
- Adding up each day
- £0.48
Your letter
23 July 2026 Dear Sir or Madam, RE: OVERDUE INVOICE [invoice number] — £1,500.00 Invoice [invoice number], dated 23 June 2026, for £1,500.00 was due for payment on 23 June 2026. It remains unpaid and is now 30 days overdue. Under the Late Payment of Commercial Debts (Interest) Act 1998 I am entitled to claim statutory interest and a fixed sum in compensation. The amount now due is: - Invoice amount: £1,500.00 - Statutory interest at 11.75% for 30 days: £14.49 - Fixed compensation: £70.00 - Total now due: £1,584.49 Interest continues to accrue at £0.48 per day until payment is received in full. I would be grateful for payment of £1,584.49 within 7 days of the date of this letter. If there is a reason the invoice has not been paid, or if you would like to discuss a payment arrangement, please contact me and I will do what I can to help. If payment is not received and I do not hear from you, I reserve the right to recover the debt through the courts without further notice. Yours faithfully, [your business name]
Written for business-to-business invoices, which is what the Act covers — it doesn't apply to private customers. This is general information, not legal advice. For a large debt, or if they dispute it, talk to a solicitor before going further.
What you're entitled to
Under the Late Payment of Commercial Debts (Interest) Act 1998, when one business owes another and pays late, you can claim:
- Statutory interest of 8% above the Bank of England base rate, running from the day after payment was due
- Fixed compensation per invoice — £40 under £1,000, £70 up to £9,999.99, £100 at £10,000 and over
- Reasonable recovery costs beyond that fixed sum, if chasing has genuinely cost you more
Two things worth knowing
It only covers business customers.If a private householder hasn't paid, this Act doesn't apply and the route is different.
You don't have to claim every penny.Plenty of people work out the figure, then tell the customer they'll waive the interest if the invoice is settled this week. Knowing the number gives you something to trade.