Free tool
Late fee calculator
Estimate an overdue invoice balance with a flat fee, a monthly percentage, or annual simple interest.
Prorated across 30-day months.
Late fee
$18.75
Total due
$1,268.75
1.50% of the invoice amount
Calculation note
3.00% monthly fee prorated over 15 days.
Frequently Asked Questions
Does this decide what I am legally allowed to charge?
No. This tool only estimates amounts from the fee model you enter. Always check your contract terms and local legal rules before charging a late fee.
Why are monthly late fees prorated here?
This calculator uses a simple 30-day prorated approach so it stays neutral across countries and contract styles. If your agreement uses full started months, update the figure manually.
Should I add a grace period?
A short grace period can reduce disputes, especially for recurring clients. Use the number that matches your invoice terms or service agreement.
Guides
Finorly AI Invoice Maker
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