Invoice Late Fee Calculator
Calculate accumulated late fees on an overdue invoice as of today. Free to use, no signup required for occasional use.
What is the Invoice Late Fee Calculator?
The Invoice Late Fee Calculator helps freelancers, contractors, and small businesses figure out exactly how much late fee has accumulated on an overdue invoice. Enter the original invoice amount, the due date, and the late fee percentage you charge per month, and the tool calculates how many days have passed since the due date, converts that into months, and applies your late fee rate to determine both the late fee amount and the new total amount due. This removes the manual date math and rate calculation that often causes confusion or errors when following up with clients on overdue payments, and gives you a clear, defensible figure to include in a payment reminder or updated invoice.
How to use it
Enter the original invoice amount. Enter the due date that was on the invoice. Enter your late fee percentage charged per month — many contracts specify something like 1.5% per month, but use whatever rate is stated in your agreement. Click 'Calculate' to see how many days and months late the payment is, the accumulated late fee amount, and the total amount now due including that fee.
Frequently asked questions
How is 'months late' calculated from days?
The tool converts days late into months using a standard 30-day month, then applies your monthly late fee percentage proportionally to that figure.
Is charging a late fee always legal?
Late fee terms and limits vary by jurisdiction and should generally be agreed to in your contract or invoice terms in advance; check local regulations if you're unsure.
Does the late fee compound month over month?
This tool applies a simple late fee proportional to the time elapsed rather than compounding fees on top of previous fees.
What if the invoice isn't overdue yet?
If today's date is before the due date, the days-late figure will be zero and no late fee will apply.