Invoice Late Fee Calculator

Work out the late fee or interest owed on an overdue invoice.

$
1.5% a month is 18% a year.
$
Fractions and decimals both work.
Late Charges
Interest charge
Flat fee
Annual rate
Interest per day
Total Due

Invoices

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How to Calculate a Late Fee

Late fees are usually either a flat charge, a percentage interest rate, or both, starting after any grace period. This page figures interest by the day on the unpaid amount.

Interest = invoice × monthly rate × 12 × days late ÷ 365
Total late charge = interest + flat fee

Worked Example

Tips

Late fees must be in your contract or invoice terms before the work is done. State laws limit late fees and interest, especially for consumers; this page doesn't check those limits.