Free late payment interest calculator UK.
Enter the invoice amount and due date to calculate statutory late payment interest, fixed compensation, and a sentence you can paste into a chasing letter. There is no sign-up, and you can export the result for Excel or download the 50-invoice workbook.
Single-invoice estimate.
The default uses the 3.75% reference Bank Rate for debts becoming late from July to December 2026, plus an 8 percentage-point statutory margin. Check the rate for when your debt became late, not just today’s Bank Rate. Rates remain editable and are not selected automatically by date. Your entries are calculated in this browser and are not uploaded by this tool.
Sources and freshness
Sources verified: . Default reference Bank Rate: 3.75%. For debts becoming late from January to June, check the rate on the preceding 31 December; for July to December, check the rate on 30 June. Check historical rates for older debts.
Rates and compensation Editable statutory defaults
Copy-ready wording
Enter the invoice details to create a sentence for your chasing letter.
Scope: drafting aid for qualifying UK business-to-business commercial debts. Basis: simple interest over a 365-day year using the amount still unpaid and one rate period. Partial-payment dates are not modelled. Check the contract and eligibility before relying on or sending these figures. This is not legal advice.
Free: export this result or use the 50-invoice workbook. Nothing is sent automatically.
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.
Formula used.
Annual statutory rate = applicable reference Bank Rate + 8 percentage points. Daily interest = invoice amount x annual statutory rate / 365. Interest estimate = daily interest x days overdue.
For qualifying overdue invoices, 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.
Late payment interest calculator questions.
When can statutory late payment interest apply?
The statutory regime can apply to qualifying late payments between businesses. Contract terms, disputes and the circumstances of the debt can change what is appropriate to claim.
What rate does this calculator use?
The default annual rate is the reference Bank Rate plus 8 percentage points. The reference Bank Rate depends on when the debt became late. Use the preceding 31 December rate for January to June, or the 30 June rate for July to December. Both inputs are editable; the calculator does not automatically choose historical rates or split partial-payment periods.
What fixed compensation can be added?
The statutory bands are £40 below £1,000, £70 from £1,000 to below £10,000, and £100 from £10,000 upwards. Use the reset button to restore the band.
Can I calculate interest for several invoices in Excel?
Yes. Export one result as a CSV or use the free 50-invoice Excel workbook for a debtor list. The workbook includes editable rates, formulas, filters and compensation bands.
Does SHVL send a demand or contact the customer?
No. The calculator creates figures and draft wording only. The optional chase pack creates editable files for review, and nothing is sent automatically.
Need the calculation for a whole aged-debtors list?
Export this result for Excel, use the 50-invoice workbook, or let SHVL handle the full batch: upload the CSV, preview the totals, then create the reviewable ZIP after checkout.
Download 50-invoice Excel calculator Upload CSV and preview Open sample pack first