Invoice late feeLive calculation
Overdue invoice calculation
Free invoice late fee calculator
Calculate in your browser
Enter the unpaid invoice balance, an agreed flat fee or percentage rate, and the number of charge periods to estimate the late fee and updated amount due.
Free, no sign-up, and the entered values stay in your browser.
Formula
How the calculation works
Enter the unpaid invoice balance, an agreed flat fee or percentage rate, and the number of charge periods to estimate the late fee and updated amount due.
Late fee = flat fee × periods + unpaid balance × percentage rate × periods. Updated balance = unpaid balance + late fee.Charge a late fee only when the customer agreed to the term and applicable law permits it. Check local notice, rate and compounding rules before updating an invoice.
Use the result
Move from calculation to a customer document.
Confirm the measurements, rates, tax treatment and project scope before relying on an estimate. Keep the calculation with the customer record, then place the verified figures in an itemized estimate, quote or invoice.
These browser calculations support planning and pricing. They do not replace field measurements, supplier quotations, payroll, accounting, tax, lending or professional advice.
Frequently asked questions
Questions about free invoice late fee calculator
Can I add a late fee to any overdue invoice?
No. The fee should be supported by the accepted contract or invoice terms and allowed by the law that applies to the transaction.
Should a late fee be flat or percentage based?
Use the method stated in the agreed payment terms. A flat charge is a fixed amount per period, while a percentage charge changes with the unpaid balance.
Does this calculator compound late fees?
No. The percentage is applied to the original unpaid balance for each entered period. It does not charge interest on earlier late fees.
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