How much late fee can I charge on an invoice?

A common late fee is 1.5% per month (18% per year) or a flat fee, but the legal maximum depends on your country/state and what your contract or invoice terms specify. Always state your late-fee policy on the invoice up front.

How is invoice late fee interest calculated?

Multiply the unpaid amount by the daily interest rate (annual rate ÷ 365) and by the number of days the invoice is overdue, then add any flat fee.

Late Fee Calculator

Work out the interest and late fee on an overdue invoice. Enter the amount, your rate, and how many days late it is.

Invoice amount

Days overdue

Annual interest rate (%)

Flat late fee (optional)

For guidance only — the late fee you can legally charge depends on your contract terms and local law.

Stop calculating late fees by hand.

PaidPilot tracks every overdue invoice and auto-sends polite, escalating reminders until you're paid. Open the full app, free →

Late fee FAQ

How much late fee can I charge?

A common policy is 1.5% per month (18%/yr) or a flat fee, but the legal maximum depends on your country/state and your contract. State your late-fee terms on the invoice before the work, so they're enforceable.

How is the interest calculated?

Daily interest = amount × (annual rate ÷ 365). Multiply that by the number of days overdue, then add any flat fee. This calculator uses simple (non-compounding) interest.

Should I actually charge it?

Often the threat is enough. A clear, polite reminder that mentions the accruing late fee gets most invoices paid — which is exactly what PaidPilot automates.

Late Fee Calculator

Result

Late fee FAQ