Late fee calculator
See what a late fee comes to so far. Enter the invoice amount, the due date or the days late, and either a percent per month or a flat fee.
How the fee is counted
A month here is 30 days. One day late at 1.5% a month is 1.5% divided by 30, times the invoice. Thirty days late is the full 1.5%. The result is rounded to the nearest cent. A flat fee is different: it is the dollar amount you type, added once, and only after the due date.
The number is not permission to charge it. Late fees have to be allowed by the contract and by state law. If you are not sure what applies where you and the client are, leave the fee off. This page will still do the arithmetic. It will not tell you that the fee is legal.
When the fee is already in the agreement, say the original invoice, the fee, and the new total in the email. The late fee email is the wording. If you need a reminder with no fee in it, the overdue invoice email writes that note for you to copy.
Questions
How do you calculate a late fee on an invoice?
A percent per month is spread across 30 days. The fee so far is the invoice amount, times the percent, times the days late, divided by 30. Fifteen days at 2% a month is half of a month’s fee. A flat fee is added once after the due date, and it does not grow each day. If the invoice is not late yet, the fee is $0.
Can I charge a late fee on an unpaid invoice?
Only if the contract, or the invoice the client accepted, already allows that fee, and state law allows it. This page does not decide that. If the fee isn’t written down, leave it off.
What does “so far” mean?
The percent is counted only for the days the invoice has already been late. It is not a guess about next month. A flat fee stays the same once the invoice is late.
Do you save the invoice or send an email?
No. The math runs in your browser. Nothing is stored, and nothing is sent.