Late Payment Interest Calculator
Work out the interest on an overdue invoice from the due date to the payment date at your contract or statutory rate, plus a fixed recovery amount.
Fixed recovery amount
UK business to business debts: statutory interest is 8% plus the Bank of England base rate, and the fixed sum is 40 for debts under 1,000, 70 up to 9,999.99 and 100 from 10,000 (in pounds).
Interest
71.01
Total now owed
4,871.01
Days late
45
Interest per day
1.5781
Interest = amount × rate ÷ 100 ÷ 365 × days late (simple interest)
How late payment interest is calculated
When a customer pays an invoice late, many contracts and laws let the supplier charge interest from the due date until payment. This calculator counts the days and works out simple interest on a 365 day year, plus a fixed recovery amount if one applies.
How late payment interest is calculated
Interest = invoice amount × yearly rate ÷ 100 ÷ 365 × days late
Example: 4,800 paid 45 days late at 12% a year: 4,800 × 0.12 ÷ 365 × 45 = 71.01.
Which rate can you charge?
| Where | Rule |
|---|---|
| Your contract | The rate in your terms of sale, if the customer agreed to them and local law allows it |
| United Kingdom (business to business) | Statutory interest of 8% plus the Bank of England base rate, plus fixed compensation of £40, £70 or £100 by the size of the debt |
| European Union (business to business) | At least the ECB reference rate plus 8 points, and at least €40 compensation, under the Late Payment Directive |
| Elsewhere | Rules differ by country and state; some cap the rate. Check before you charge. |
Make it easy to collect
Put your late payment terms on every invoice and quote, and send a polite reminder before charging interest. The payment reminder email generator writes the message, and the Net 30 calculator confirms the due date.
Copy the result, or save it as a PDF to attach to an email or a report. Nothing you type leaves your browser.
Features
- Days late from two dates
- Simple daily interest
- Any rate a year
- UK statutory fixed sum (40, 70, 100)
- Total now owed
- Copy or PDF
Frequently asked questions
How do I calculate interest on a late payment?
Multiply the amount by the yearly rate, divide by 365, then multiply by the days late. 10,000 at 13% for 30 days is 106.85.
What is the UK statutory late payment interest?
For business to business debts it is 8% a year above the Bank of England base rate, plus a fixed sum of £40, £70 or £100 depending on the debt.
Can I charge interest if my invoice did not mention it?
In the UK and EU, statutory interest applies to business debts even if the contract is silent. Elsewhere it usually depends on your agreed terms and local law.
Is the calculator free?
Yes. No sign up. It runs in your browser, and you can copy the result or save it as a PDF.