Invoice Late Fee

Estimate how much to charge when a client pays late. Enter the invoice balance, daily penalty rate, and number of days overdue to calculate the fee owed under simple interest terms.

Total outstanding balance before late penalties.
Enter the daily percentage penalty specified in your contract.
Count calendar days past the due date, unless your terms state otherwise.

Educational information, not professional advice.

Examples

  • $1,500 invoice at 1.5% per day for 10 days ⇒ $225 late fee
  • $4,200 invoice at 0.5% per day for 20 days ⇒ $420 late fee
  • $750 invoice at 2% per day for 5 days ⇒ $75 late fee

FAQ

Does the calculator compound interest?

No. It applies simple interest. If your agreement compounds fees, run the calculation periodically and add the new balance back into the invoice manually.

Can I add the fee to the invoice total?

Yes, provided your contract or terms of service clearly state the late fee policy. Add the result to the outstanding balance when sending reminders.

How do weekends or holidays factor in?

Unless your agreement pauses penalties on non-business days, count every calendar day past due. Adjust the input to match your policy.

Additional Information

  • Simple interest multiplies the daily rate by the outstanding balance and the number of overdue days.
  • Many jurisdictions cap late fees—review local regulations or industry standards before invoicing.
  • If your contract specifies a monthly late fee, divide it by 30 to approximate the daily percentage.

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