How do you calculate late payment interest in the UK?

For qualifying UK business-to-business debts, statutory interest is calculated using the debt amount multiplied by the annual rate of Bank of England base rate plus 8 percentage points, divided by 365, then multiplied by the number of days overdue.

What does SHVL do after the calculator?

SHVL turns an aged-debtors CSV into a reviewable ZIP containing editable Word letters, openable email drafts, an Excel calculation log, and a README. Nothing is sent automatically.

Late payment interest calculator UK

Calculate UK late payment interest before you chase.

Estimate statutory interest for a UK business-to-business overdue invoice, add the fixed compensation band, and see when a full CSV chase pack is worth creating.

Use the calculator Preview a chase pack

Single-invoice estimate.

The default Bank Rate is set to 3.75%, which was the Bank of England figure found during the June 2026 review. Always check the current official rate before sending.

Sources and freshness

Last checked: 5 June 2026. Default Bank Rate used on this page: 3.75%.

Invoice amount Days overdue Bank of England base rate (%)

Daily interest £0.00

Interest estimate £0.00

Fixed compensation £0.00

Total including principal £0.00

Worked examples at 3.75% Bank Rate.

These examples use an annual statutory rate of 11.75%: 3.75% Bank Rate plus 8 percentage points. They are examples for drafting and checking, not legal advice.

£797.24 £750 invoice, 30 days overdue: £7.24 interest plus £40 fixed compensation.

£2,618.29 £2,500 invoice, 60 days overdue: £48.29 interest plus £70 fixed compensation.

£12,447.67 £12,000 invoice, 90 days overdue: £347.67 interest plus £100 fixed compensation.

Formula used.

Annual statutory rate = Bank of England base rate + 8 percentage points. Daily interest = invoice amount x annual statutory rate / 365. Interest estimate = daily interest x days overdue.

Fixed compensation is added by invoice value: £40 below £1,000, £70 from £1,000 to below £10,000, and £100 from £10,000 upwards.

GOV.UK late commercial payments Bank of England Bank Rate Fixed compensation explainer Download Excel calculator template

Need the calculation for a whole aged-debtors list?

The free calculator is useful for one debt. SHVL is built for the batch: upload the CSV, preview the totals, then create the reviewable ZIP after checkout.

Upload CSV and preview