Late Payment Interest Calculator
Calculate the statutory interest and fixed compensation you can add to an overdue invoice under the UK Late Payment of Commercial Debts Act 1998. Know exactly what you are legally entitled to claim.
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How to use this late payment calculator
Calculate the statutory interest and compensation you can claim on overdue invoices under the Late Payment of Commercial Debts Act 1998.
- 1Enter the invoice amount
Type the original invoice total that remains unpaid.
- 2Enter the due date
Select the date the payment was originally due.
- 3Set the calculation date
Choose today or a specific date to calculate interest up to.
- 4See what you are owed
View the statutory interest (8% + Bank of England base rate) and fixed compensation amount.
Why this matters
Late payments cost UK small businesses an estimated £22 billion a year. As a tradesperson, you have a legal right to charge interest on overdue invoices. This calculator shows you exactly how much, which can be useful when chasing slow-paying clients.
Frequently asked questions
What is the Late Payment of Commercial Debts Act 1998?
The Late Payment of Commercial Debts (Interest) Act 1998 gives UK businesses the right to charge statutory interest on overdue invoices. The interest rate is 8% above the Bank of England base rate. The Act also entitles you to a fixed compensation charge (£40, £70 or £100 depending on the debt size) to cover recovery costs.
What is the current statutory interest rate for late payments?
The statutory interest rate is the Bank of England base rate plus 8%. With the BoE base rate at 4.75% (as of early 2026), the statutory rate is 12.75% per annum. This is calculated on a daily basis from the date payment was due.
How much fixed compensation can I claim?
You can claim a fixed compensation charge on top of the interest: £40 for debts under £1,000; £70 for debts between £1,000 and £9,999.99; and £100 for debts of £10,000 or more. This is per invoice and is meant to contribute towards your debt recovery costs.
Does the Late Payment Act apply to all invoices?
The Act applies to business-to-business contracts. It does not apply to debts owed by consumers (members of the public). If you are a sole trader or a limited company invoicing another business, you can use the Act.
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