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Late Payment Interest Calculator

Calculate interest accrued on overdue invoices using a simple daily interest rate method.

The original invoice or debt amount that is overdue.
The annual interest rate. UK statutory rate is 8% + Bank of England base rate.
Number of calendar days the payment is overdue.

Results

Interest Accrued$98.63
Total Amount Owed$10,098.63
Daily Rate0.00,022%/day

📖What is it?

For informational/educational purposes only. Not legal advice. Consult a qualified attorney for your situation. Late payment interest compensates creditors for delayed payments. Many jurisdictions provide statutory rates (e.g., UK Late Payment of Commercial Debts Act allows 8% over base rate).

🎯How to use

Enter the original invoice amount, the applicable annual interest rate, and the number of days the payment is overdue. The calculator outputs the accrued interest and total amount owed.

💡Example scenario

An agency is owed $10,000. The client pays 45 days late. At 8% annual rate: daily rate = 0.02192%; interest = $10,000 � 0.0002192 � 45 = $98.63; total owed = $10,098.63.

🏆Pro tip

Always include a late payment clause in your contracts specifying the interest rate and when it applies. Sending a formal demand letter with the interest calculation often prompts faster payment without needing legal action.