Late Payment Interest Calculator
Estimate simple interest on an overdue invoice.
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Try late payment interest calculator
Your entries stay in your browser. Nothing is sent to LaunchKit to perform this calculation.
Your result
How to use this tool
Apply the entered annual interest rate to the overdue balance for the number of days using 365 days per year. The applicable legal rate may differ.
How the calculation works: Interest = principal × annual rate × days ÷ 365
- Review the example values and replace them with your own figures or text.
- Press Generate result to see a calculation, transformed text or ready-to-use document.
- Copy or download the result to use it in your own workflow.
What to check before using the result
Figures are only as reliable as the data entered. Check that your inputs cover the same period, use consistent units, and reflect real fees, taxes or costs relevant to your situation. This calculator does not replace accounting, financial, legal or tax advice.