Free Invoice Late Payment Fee Calculator

Calculate the late fee owed on an overdue invoice.

Late fee terms should always be stated clearly on your invoice/contract before you can enforce them — a common approach is 1.5% per month (18% APR equivalent) on the outstanding balance, prorated daily for partial months. Check your local regulations, as some jurisdictions cap allowable late fees.

Worked Example

Example: $2,000 invoice, 1.5%/month late fee, 20 days overdue. Daily rate = 1.5%/30 = 0.05%/day. Late fee = $2,000 × 0.05% × 20 = $20.00.

Formula

Daily Rate = Monthly Rate % / 30
Late Fee = Invoice Amount × Daily Rate × Days Overdue

Worked Example

Example: $2,000 invoice, 1.5%/month late fee, 20 days overdue. Daily rate = 1.5%/30 = 0.05%/day. Late fee = $2,000 × 0.05% × 20 = $20.00.

Formula

Daily Rate = Monthly Rate % / 30
Late Fee = Invoice Amount × Daily Rate × Days Overdue