Late Fee Calculator
Enter the invoice amount, monthly late-fee rate, and days overdue to calculate the fee owed.
How to use this calculator
- 1Enter the unpaid invoice amount.
- 2Enter your monthly late-fee (interest) rate and how many days it is overdue.
- 3See the late fee and the new balance the client owes.
How the Late Fee Calculator works
A late fee compensates you for being paid late and gives clients a reason to pay on time. Most businesses charge 1–1.5% of the invoice per month, pro-rated for the days overdue. The key is to state the fee in your terms before the work starts, so it is enforceable and never a surprise.
This calculator pro-rates the monthly rate across the exact days an invoice is overdue and shows the new balance due. Check your local rules first — some states and countries cap the maximum late fee or interest you can charge.
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Create an invoice freeFrequently asked questions
What is a typical late fee?
A common late fee is 1–1.5% per month (about 12–18% a year), but always set it in your contract or invoice terms and stay within local limits.
How is a late fee calculated?
Multiply the invoice amount by the monthly rate, then pro-rate for the days overdue (days ÷ 30). This tool does it for you.
Can I charge a late fee legally?
Usually yes if you stated it in your terms before the work, but caps vary by state/country. Check your local rules and disclose the fee up front.
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