Late Payment Interest Calculator 2026
Instantly calculate statutory interest, daily interest, and fixed compensation for overdue invoices. Essential for B2B debt recovery and enforcing your late payment rights.
Invoice & Overdue Details
Enter the invoice amount, days overdue, and interest rate
The original net amount of the unpaid invoice.
Number of days past the agreed payment due date.
UK statutory rate is currently 8% above Bank of England base rate (e.g., 13% if base is 5%).
Fixed sum you can claim per invoice under the Late Payment of Commercial Debts Act.
How many decimal places to show in monetary results.
Debt Recovery Analysis
Interest accrued, fixed compensation, and total amount due
Enter the invoice details above, then click Calculate Interest & Compensation to see your statutory claim breakdown.
Fixed Compensation Tiers
Under the Late Payment of Commercial Debts (Interest) Act 1998, businesses can claim a fixed statutory compensation amount on top of interest for each late invoice.
| Debt Amount | Fixed Compensation | Eligibility Notes |
|---|---|---|
| Under £1,000 | £40.00 | Claim for any commercial debt up to £999.99 |
| £1,000 – £9,999.99 | £70.00 | Claim for debts between £1,000 and £9,999.99 |
| £10,000 or more | £100.00 | Claim for any commercial debt of £10,000 or above |
Late Payment Interest Calculator FAQ
Everything you need to know about statutory interest, fixed compensation, and enforcing your late payment rights under UK law.
Late payment interest is calculated by applying an annual interest rate to the overdue amount for the number of days the payment is late. The standard formula is: (Debt Amount × Annual Interest Rate) ÷ 365 × Days Overdue. For example, a £1,000 invoice at 8% annual interest, 30 days late, would accrue £6.58 in interest (£1,000 × 0.08 ÷ 365 × 30).
Under the UK Late Payment of Commercial Debts (Interest) Act 1998, the statutory interest rate for B2B transactions is 8% above the Bank of England base rate. For example, if the base rate is 5%, the statutory late payment interest rate is 13%. This applies automatically to commercial contracts unless a substantial alternative remedy was agreed upon.
Yes, under UK law, businesses and self-employed individuals can claim fixed statutory compensation on top of interest for late B2B payments. The tiers are: £40 for debts under £1,000; £70 for debts between £1,000 and £9,999.99; and £100 for debts of £10,000 or more. This compensation cannot be contractually excluded.
You can start charging interest the day after the payment due date. If no specific due date was agreed, interest can be claimed 30 days after the invoice was issued or the goods/services were delivered, whichever is earlier. For public sector contracts, this period is strictly 30 days.
The statutory right to claim 8% above the Bank of England base rate plus fixed compensation applies specifically to Business-to-Business (B2B) and Business-to-Consumer (B2C) commercial debts. For standard consumer-to-consumer debts, or where a different interest rate is specified in a contract, the agreed contractual rate or standard contractual terms apply instead.
To calculate daily interest, divide the annual interest amount by 365 (or 366 in a leap year). First, find the annual interest: Debt Amount × (Annual Rate ÷ 100). Then divide by 365. For example, £5,000 at 10% annual interest is £500 per year. Divided by 365, the daily interest is £1.37 per day.