Invoice Late Payment Calculator
Updated on 22 Oct 2026 · Checked by Aotob
$5,000 paid 45 days late earns $73.97 in interest.
With the $0 fee you can claim $5,073.97 in total.
Late payment interest
$73.97
Charge what your contract or invoice terms allow. Put the rate on every invoice so it is agreed up front.
Show the working
5,000.00 × 12% ÷ 365 × 45 = 73.97
Interest by days late
| Days late | Interest | Total |
|---|---|---|
| 15 | 24.66 | 5,024.66 |
| 30 | 49.32 | 5,049.32 |
| 60 | 98.63 | 5,098.63 |
| 90 | 147.95 | 5,147.95 |
| 180 | 295.89 | 5,295.89 |
| 365 | 600.00 | 5,600.00 |
Questions people ask
Can I charge interest on a late invoice?
In the UK and Ireland, yes, by law, on business-to-business invoices: 8% over the central bank rate, plus a fixed £40 to £100 or €40 to €100. Elsewhere you can charge what your contract or invoice terms set.
Is there a legal limit?
In the US, state usury laws cap interest; 1% to 1.5% a month is common on invoices. Keep it reasonable and in your terms.
How do I make it stick?
Put the rate and payment terms on every quote and invoice, and send a polite reminder before charging.
Updated 22 Oct 2026Source: UK Late Payment of Commercial Debts (Interest) Act 1998; EU Late Payment DirectiveChecked by AotobNot legal advice. Check the current central bank rate.Report an issue