Late payment interest on a business invoice is the unpaid amount × the yearly statutory rate × the days late ÷ 365. The UK rate is 8% plus the Bank of England base rate; Ireland's is the ECB rate plus 8 points. For debts that become late from 1 July to 31 December 2026 that is 11.75% in the UK and 10.40% in Ireland. Each late invoice also earns a fixed £40 to £100, or €40 to €100.
Interest and compensation you can claim
£93.18
on top of the £2,400.00 invoice, 30 days late
Opens the free invoice maker with three lines filled in: the unpaid invoice, the interest and the compensation. The figures travel inside the link and are not stored.
Rates checked 8 October 2026 against legislation.gov.uk, GOV.UK, the Bank of England, irishstatutebook.ie, the Irish Department of Enterprise and the ECB. For business-to-business debts only; consumer debts and public-body rules differ.
Count the days from the day after the due date up to and including the day you are paid. Both laws give simple interest, so the interest itself never earns interest. The calculator keeps the daily figure unrounded and rounds only the result; GOV.UK's own example rounds the daily amount to the penny first, which can make its total a few pence lower.
8% a year plus the Bank of England base rate in force on 31 December (for interest that starts running from 1 January to 30 June) or on 30 June (from 1 July to 31 December). That rate then applies for as long as the invoice stays unpaid.
The ECB main refinancing rate before 1 January or 1 July, plus 8 percentage points. The department tells you to use the daily rate in operation on the date the payment became overdue.
Sources: 1998 Act sections 1 and 4(2); 2002 Order, article 4 (the Scottish order sets the same rate); GOV.UK; S.I. No. 580 of 2012, regulations 4 and 5; Irish department FAQ. Last checked 8 October 2026.
Find the half-year in which interest started running (the day after the due date). The rate in that row applies to the whole debt.
| Interest starts running | Base rate on | Base rate | Statutory rate |
|---|---|---|---|
| 1 July to 31 December 2026 | 30 June 2026 | 3.75% | 11.75% |
| 1 January to 30 June 2026 | 31 December 2025 | 3.75% | 11.75% |
| 1 July to 31 December 2025 | 30 June 2025 | 4.25% | 12.25% |
| 1 January to 30 June 2025 | 31 December 2024 | 4.75% | 12.75% |
| 1 July to 31 December 2024 | 30 June 2024 | 5.25% | 13.25% |
| 1 January to 30 June 2024 | 31 December 2023 | 5.25% | 13.25% |
| 1 July to 31 December 2023 | 30 June 2023 | 5.00% | 13.00% |
| 1 January to 30 June 2023 | 31 December 2022 | 3.50% | 11.50% |
| 1 July to 31 December 2022 | 30 June 2022 | 1.25% | 9.25% |
| 1 January to 30 June 2022 | 31 December 2021 | 0.25% | 8.25% |
| 1 July to 31 December 2021 | 30 June 2021 | 0.10% | 8.10% |
| 1 January to 30 June 2021 | 31 December 2020 | 0.10% | 8.10% |
| 1 July to 31 December 2020 | 30 June 2020 | 0.10% | 8.10% |
| 1 January to 30 June 2020 | 31 December 2019 | 0.75% | 8.75% |
Base rates from the Bank of England's Official Bank Rate history: 3.75% since 18 December 2025, held on 17 September 2026 with the next decision due on 5 November 2026. Last checked 8 October 2026. The rate for interest starting from 1 January 2027 depends on the base rate on 31 December 2026; until that is known the calculator uses 3.75% and says so.
| Half-year | ECB rate | Late payment interest |
|---|---|---|
| 1 July to 31 December 2026 | 2.40% | 10.40% |
| 1 January to 30 June 2026 | 2.15% | 10.15% |
| 1 July to 31 December 2025 | 2.15% | 10.15% |
| 1 January to 30 June 2025 | 3.15% | 11.15% |
| 1 July to 31 December 2024 | 4.25% | 12.25% |
| 1 January to 30 June 2024 | 4.50% | 12.50% |
| 1 July to 31 December 2023 | 4.00% | 12.00% |
| 1 January to 30 June 2023 | 2.50% | 10.50% |
| 1 July to 31 December 2022 | 0.00% | 8.00% |
| 1 January to 30 June 2022 | 0.00% | 8.00% |
| Half-year | ECB rate | Late payment interest |
|---|---|---|
| 1 July to 31 December 2021 | 0.00% | 8.00% |
| 1 January to 30 June 2021 | 0.00% | 8.00% |
| 1 July to 31 December 2020 | 0.00% | 8.00% |
| 1 January to 30 June 2020 | 0.00% | 8.00% |
| 1 July to 31 December 2019 | 0.00% | 8.00% |
| 1 January to 30 June 2019 | 0.00% | 8.00% |
| 1 July to 31 December 2018 | 0.00% | 8.00% |
| 1 January to 30 June 2018 | 0.00% | 8.00% |
| 1 July to 31 December 2017 | 0.00% | 8.00% |
| 1 January to 30 June 2017 | 0.00% | 8.00% |
| 1 July to 31 December 2016 | 0.00% | 8.00% |
| 1 January to 30 June 2016 | 0.05% | 8.05% |
| 1 July to 31 December 2015 | 0.05% | 8.05% |
| 1 January to 30 June 2015 | 0.05% | 8.05% |
| 1 July to 31 December 2014 | 0.15% | 8.15% |
| 1 January to 30 June 2014 | 0.25% | 8.25% |
| 1 July to 31 December 2013 | 0.50% | 8.50% |
| 16 March to 30 June 2013 | 0.75% | 8.75% |
Worked out from the ECB main refinancing rate history and identical to the table the Irish Department of Enterprise, Tourism and Employment publishes (10.40% from 1 July 2026). The ECB raised its rate to 2.65% from 16 September 2026, which will set the rate from 1 January 2027 unless it changes again before then. Last checked 8 October 2026.
| UK (section 5A of the Act) | Ireland (Schedule to S.I. 580/2012) |
|---|---|
| £40 if the debt is under £1,000 | €40 if it does not exceed €1,000 |
| £70 from £1,000 to under £10,000 | €70 above €1,000, up to €10,000 |
| £100 for £10,000 or more | €100 above €10,000 |
Watch the edges: an invoice of exactly 1,000 earns £70 in the UK but €40 in Ireland, and one of exactly 10,000 earns £100 but €70. The fixed sum applies once interest starts running, once per invoice. Where your real costs of chasing the debt are higher, both laws let you claim the reasonable difference as well (section 5A(2A) of the Act; regulation 9(3) in Ireland).
Sources: section 5A; GOV.UK, claim debt recovery costs; S.I. No. 580 of 2012, regulation 9 and Schedule. Last checked 8 October 2026.
Sources: section 4 of the Act; GOV.UK, when a payment becomes late; S.I. No. 580 of 2012, regulation 2, as amended by S.I. No. 196 of 2014 and S.I. No. 281 of 2016. Last checked 8 October 2026.
UK: no. Section 4(2) of the Act says interest starts on the day after the due date "at the rate prevailing under section 6 at the end of the relevant day", and article 4 of the 2002 Order takes the base rate on the 30 June or 31 December immediately before interest starts. So one rate covers the whole debt. Some calculators switch to a new rate each time the Bank of England moves; the legislation does not.
Ireland: the department uses one rate. Its FAQ multiplies the debt by the days late and by the daily rate in operation on the date the payment became overdue. Regulation 5(2) also says each half-year's reference rate applies "for the period" from 1 January or 1 July, which some read as changing the rate for the days in each half-year. When a debt runs past one of those dates, the calculator shows both figures and lets you pick.
Statutory interest and the fixed compensation are for debts between businesses: in the UK both sides must be acting in the course of a business (which includes government departments and public authorities), and the Irish Regulations cover transactions between undertakings and between undertakings and public authorities. They do not apply to consumers. Public bodies have their own payment limits (30 days in both countries), so check the contract or the body's terms. If your contract sets its own late payment interest, that rate replaces the statutory one: in the UK when it is a substantial remedy (sections 8 and 9 of the Act), in Ireland when it is not grossly unfair to you (regulation 5(3)).
This page explains the law as published; it is not legal advice. For a disputed or large debt, speak to a solicitor or, in the UK, the Office of the Small Business Commissioner.
Multiply the unpaid amount by the yearly rate and divide by 365 to get the interest for one day, then multiply by the number of days late. £2,400.00 at 11.75% is £282.00 a year, or £0.77 a day; 54 days late comes to £41.72. Count from the day after the due date up to the day you are paid. It is simple interest, so you never charge interest on interest.
11.75% a year for a debt that becomes late between 1 July 2026 and 31 December 2026: 8% plus the Bank of England base rate of 3.75% in force on 30 June 2026. The base rate has been 3.75% since 18 December 2025. The rate stays the same until the debt is paid.
10.40% a year for payments that become overdue between 1 July 2026 and 31 December 2026: the ECB main refinancing rate of 2.40% plus 8 percentage points. From 1 January 2026 to 30 June 2026 it was 10.15%. The Department of Enterprise, Tourism and Employment publishes the rate for each half-year.
Yes, on a debt between businesses. In the UK section 1 of the 1998 Act writes the right to statutory interest into the contract, and in Ireland Regulation 4 gives it without the need for a reminder. If your contract sets its own late payment interest, that applies instead: in the UK only if it is a substantial remedy, and in Ireland only if it is not grossly unfair to you.
Yes. GOV.UK says you can charge the fixed sum once for each payment, so every late invoice carries its own amount, set by the size of that invoice. The Irish department bands the compensation by invoice value in the same way. Both laws also let you claim reasonable recovery costs above the fixed sum, such as a debt collection agency fee.
Not in the UK. Section 4(2) of the Act fixes the rate at the end of the due date, using the base rate on the 30 June or 31 December before interest starts. A debt that became late in June 2025 carries 12.75% (the 4.75% base rate on 31 December 2024, plus 8%) until it is paid, although the base rate was already 4.25% by then and fell twice more that year. In Ireland the department applies the rate in force on the day the payment became overdue; the calculator also shows what the half-year reading of Regulation 5 would give.
No. The UK Act and the Irish Regulations cover payments between businesses, including public bodies buying from businesses. Debts owed by private individuals follow different rules, so do not add statutory interest or this compensation to an invoice for a consumer.
In the UK the payment is late 30 days after the later of the day your customer received the invoice and the day you delivered the goods or services. In Ireland payment is due 30 calendar days after the later of those days and interest runs from the next day. Choose "No date agreed" in the calculator and it works out the date for you.
GOV.UK advises sending a new invoice when you decide to add interest to the money you are owed. The button under the result opens the free invoice maker with three lines filled in (the unpaid invoice, the interest and the compensation), ready to download as a PDF.
Every rate and rule on this page was last checked on 8 October 2026. The rates move when the Bank of England or the ECB changes its rate; the tables above show the date each one took effect.