Free tool
UK late payment interest calculator
Work out how much statutory interest and fixed recovery compensation you can add to an overdue commercial invoice. Enter the amount and the date it was due — the figures update as you type. Nothing is uploaded; the calculation runs entirely in your browser.
Your invoice
Statutory interest is the Bank of England base rate plus 8%. Check the current base rate and update the field if it has changed.
What you can claim
Statutory interest and the fixed recovery fee apply to commercial debts. They do not apply when your customer is a consumer, so only the invoice amount is shown.
This invoice is not overdue yet, so no interest has accrued.
How UK statutory late payment interest works
If you supply goods or services to another business or a public authority and they pay late, the Late Payment of Commercial Debts (Interest) Act 1998 lets you charge interest plus a fixed sum toward your recovery costs. Statutory interest is the Bank of England base rate plus 8%, accruing daily from the day after payment was due until the day you are paid.
The fixed recovery fee bands
On top of interest, you can add a fixed amount per unpaid invoice:
| Invoice amount | Fixed sum you can claim |
|---|---|
| Up to £999.99 | £40 |
| £1,000 to £9,999.99 | £70 |
| £10,000 or more | £100 |
Worked example
A £1,250 invoice to a business customer is 30 days overdue, with a base rate of 3.75%. The interest rate is 11.75%, so daily interest is £1,250 × 11.75% ÷ 365 = £0.40. Over 30 days that is £12.07. The invoice sits in the £1,000–£9,999.99 band, so you can add £70. Total claim: £1,332.07.
Do I have to charge interest?
No — it is a right, not an obligation. Many suppliers mention the figure in a reminder without applying it straight away. Naming the number often prompts payment on its own, because it shows you know where you stand.
What if my contract sets a different rate?
If your contract provides a substantial remedy for late payment, that rate applies instead of the statutory one. If the contract is silent, or its rate is not a substantial remedy, statutory interest applies.
Can I claim more than the fixed sum?
If your reasonable recovery costs exceed the fixed sum — for example if you instruct a debt recovery agent — you can claim the difference on top.
What the Commercial Payments Bill will change
None of this is law yet. The Commercial Payments Bill was introduced to Parliament in May 2026 and is still going through it, with the government promising a lead-in period before the powers commence. The figures this calculator produces follow the rules in force today. The Bill is worth knowing about because it strengthens the position you are already in:
- Statutory interest in every commercial contract. The right to interest at 8% above the Bank of England base rate would be mandated across commercial contracts, so a customer could no longer negotiate you down to a lower rate.
- A 60-day ceiling on payment terms, with strictly limited exemptions, falling to 45 days after a five-year transition.
- A fixed sum for late or unevidenced disputes. If a customer raises a dispute late, or without enough information to support it, you would be entitled to a fixed payment.
- A Small Business Commissioner with teeth — powers to investigate payment practices, make binding interim decisions outside court, and impose financial penalties.
Sources: Commercial Payments Bill overview and the government response to the late payment consultation (24 March 2026). Check the current status before relying on any of it — this page is not legal advice.
Next step: send the chase
Knowing the number is half the job. ChaseKit takes the same calculation and writes a polite, firm, or final reminder around it, with the payment breakdown ready to attach. Build a free chase email, or see a real sample pack.
This calculator is an admin aid based on GOV.UK guidance on late commercial payments. It is not legal advice. Check your contract and the current base rate before relying on a figure.