Late Payment Interest Calculator (UK)
Work out the statutory interest and compensation you can claim on a late business invoice in the UK: 8% plus the Bank of England base rate.
New: please check your results.
Uses the Bank of England base rate, last checked 28 October 2026. These can change, often at the Budget, so confirm with the Bank of England and legislation.gov.uk before relying on the result.
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- Statutory interest
- £46.36
- Fixed compensation
- £70.00
- Total you can claim
- £116.36
- Interest per day
- £0.77
- Interest rate
- 11.75%
- Days late
- 60 days
- Base rate used
- 3.75% (30 June 2026)
What it does
If another business pays your invoice late, UK law lets you charge interest at 8% a year above the Bank of England base rate, plus a fixed sum for the cost of chasing it. Enter the amount, the date payment was due and the date it was paid (or today) to see how much you can claim. This is called statutory interest, and it applies unless your contract sets a different, fair rate.
How to use it
- Invoice amount
The amount still unpaid, including VAT.
- Payment was due
The date the invoice should have been paid by, under your agreed terms. If you didn't agree a date, it's 30 days after the customer received the invoice (or the goods or service, if later).
- Date paid (or today)
The date the customer paid. If they haven't paid yet, leave it as today: interest keeps building every day.
Common uses
- Adding interest to a reminder for an overdue invoice.
- Working out what to claim in a letter before action or a small claim.
- Showing customers the cost of paying late, to encourage paying on time.
- Checking the VAT on an invoice. Try the VAT Calculator (UK)
- Working out how many days an invoice is overdue. Try the Days Between Dates Calculator
The formula
Rate = 8% + reference rateInterest per day = amount × rate ÷ 365Interest = interest per day × days lateCompensation: £40 (debt under £1,000), £70 (£1,000 to £9,999.99), £100 (£10,000 or more)Where:
- Reference rate
- the Bank of England base rate on 31 December (if interest starts between January and June) or 30 June (if it starts between July and December)
Simple interest: it's charged on the original amount only, not on interest already added. The rate is fixed by when the debt became late and doesn't change while it's unpaid.
Worked example
An invoice for £2,400, due 31 March 2026 and paid 30 May 2026:
- The debt became late in the half-year that uses the base rate on 31 December 2025: 3.75%
- Rate: 8% + 3.75% = 11.75%
- Interest per day: £2,400 × 11.75% ÷ 365 = about £0.77
- For 60 days late: £2,400 × 11.75% × 60 ÷ 365 = £46.36
- Fixed compensation for a debt of £1,000 to £9,999.99: £70.00
You can claim £116.36 on top of the invoice.
Questions people ask
Who can charge statutory late payment interest?
Any business, including sole traders, owed money by another business or by the public sector, under the Late Payment of Commercial Debts (Interest) Act 1998. It doesn't apply to money owed by consumers, and it doesn't apply if your contract already sets a substantial late payment charge.
Can I charge the compensation as well as interest?
Yes. The fixed sum (£40, £70 or £100, depending on the debt) is per invoice and is on top of the interest. If your reasonable costs of recovering the debt were higher, you can claim the difference too.
Do I need to have warned the customer first?
No: the right comes from the law, not your terms. It's still worth stating your payment terms and late payment policy on every invoice, and telling the customer the interest you're adding when you chase it.
Last checked 28 October 2026 · Last rev. 31 October 2026 · dae8