Free Tool
Late Fee Calculator
To calculate a late fee on an overdue invoice, multiply the invoice amount by your state's annual interest rate and the days overdue, then divide by 365. Enter your numbers in the calculator to get interest, flat fees, and the total amount due.
Calculation Results
Original Invoice $0.00
Interest Accrued $0.00
Flat Late Fee $0.00
Total Due $0.00
Formula: Interest = (Principal × Rate × Days) ÷ 365
Important Disclaimer
This calculator is for educational purposes only. It is not legal or financial advice. Late fee laws vary by state and contract terms. Always consult with a qualified attorney before charging late fees. Verify that your contract terms comply with your state's usury laws.
Know Your State's Laws
Check the maximum interest rates and late fee rules for your state.
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