UK Late Payment Calculator
UK late payment interest calculator: what you can charge on a late invoice
Work out the statutory interest and fixed-sum compensation you can claim on an overdue business invoice under the Late Payment of Commercial Debts (Interest) Act 1998. The numbers update as you drag.
Your overdue invoice
Default 11.75% applies when interest started running 1 Jul – 31 Dec 2026: the 3.75% Bank Rate on 30 Jun 2026 plus 8 points. The rate stays fixed for the life of the debt, so for an older debt use the rate for when it fell due (table below).
What you can claim
£48.29
Statutory interest
£70.00
Fixed-sum compensation
£1.61
Interest per day
£118.29
Total you can claim on top
Total amount now due
£5,118.29
Debt + statutory interest + fixed-sum compensation.
This calculator estimates simple statutory interest (actual/365) plus the fixed sum under the Late Payment of Commercial Debts (Interest) Act 1998, using the 3.75% Bank of England base rate in force on 30 Jun 2026. Your contract may set its own late-payment terms. It is general information, not legal advice — check with a qualified adviser before issuing a formal demand.
The rules, briefly
What the Late Payment Act lets you claim
When another business pays you late, the law gives you interest and compensation automatically, with no clause in your contract needed. These are the UK rules; for customers in the EU, use the EU late payment calculator instead.
Base rate + 8 points
Statutory interest is 8% a year over the Bank of England base rate: 11.75% for debts where interest started running 1 Jul – 31 Dec 2026.
£40, £70 or £100 per invoice
On top of interest you can claim a fixed sum per debt: £40 under £1,000, £70 up to £9,999.99, £100 from £10,000. Reasonable recovery costs above that can be claimed too.
30 days if nothing was agreed
With no agreed date, a payment is late 30 days after the customer gets the invoice or you deliver, whichever is later. Business terms should usually stay within 60 days.
The rate is fixed per debt
Use the base rate in force on 30 June or 31 December before interest started. A later rate change does not alter the interest on an invoice that is already late.
Which rate applies to your debt
Find when statutory interest started running on your invoice (the day after it fell due).
| Interest started | Base rate on | Base rate | Statutory rate |
|---|---|---|---|
| 1 Jul – 31 Dec 2026 | 30 Jun 2026 | 3.75% | 11.75% |
| 1 Jan – 30 Jun 2026 | 31 Dec 2025 | 3.75% | 11.75% |
| 1 Jul – 31 Dec 2025 | 30 Jun 2025 | 4.25% | 12.25% |
| 1 Jan – 30 Jun 2025 | 31 Dec 2024 | 4.75% | 12.75% |
| 1 Jul – 31 Dec 2024 | 30 Jun 2024 | 5.25% | 13.25% |
| 1 Jan – 30 Jun 2024 | 31 Dec 2023 | 5.25% | 13.25% |
“8 per cent per annum over the official dealing rate”, taken as the rate in force on 30 June or 31 December immediately before interest starts to run.
Sources: SI 2002/1675, gov.uk late commercial payments guidance and the Bank of England Bank Rate history.
FAQ
UK late payment interest — common questions
How much interest can I charge on a late payment in the UK?
Statutory interest is 8% a year over the Bank of England base rate, under the Late Payment of Commercial Debts (Interest) Act 1998. For a debt whose interest started running between 1 Jul – 31 Dec 2026, that is 11.75% (3.75% + 8). It is simple interest, worked out per day: the debt times the rate, divided by 365, times the days it is late.
Which Bank of England base rate do I use?
The base rate in force on 30 June for interest that starts running between 1 July and 31 December, or on 31 December for interest that starts running between 1 January and 30 June (SI 2002/1675, article 4). That rate stays fixed for the whole debt: if the Bank cuts or raises rates later, the interest on an invoice that is already late does not change.
How much compensation can I add to a late invoice?
A fixed sum per debt, on top of interest: £40 for a debt up to £999.99, £70 from £1,000 to £9,999.99, and £100 for £10,000 or more. You can charge it once per invoice, and you can also claim reasonable costs beyond the fixed sum each time you try to recover the debt.
When does a UK invoice legally count as late?
On the day after the payment date you agreed. If you did not agree one, the payment is late 30 days after the customer receives the invoice or you deliver the goods or service, whichever is later. Agreed payment periods should usually be within 60 days between businesses (longer only if it is fair to both sides) and within 30 days for public authorities.
Does the Late Payment Act apply to every customer?
It applies when both sides are acting in the course of a business, which includes sole traders. It does not apply to sales to consumers. It covers contracts for goods and services governed by the law of any part of the UK.
Can my contract set a different late-payment rate?
Yes. If your contract sets its own interest for late payment, that applies instead of statutory interest, as long as it is a substantial remedy. A token rate that does not properly compensate you can be set aside, and statutory interest then applies.
Knowing the number is the easy part. Collecting it is the work.
DueTrail connects to Xero or QuickBooks, works out this statutory interest and compensation on every overdue invoice, and can quote it in the reminders you approve and in the portal where customers promise a date.