Freelance Late Payment Interest Calculator

If a client pays late and your contract includes a late-payment interest clause, use this calculator to figure out exactly how much extra they owe based on days overdue.

Interest Owed
Original Invoice Amount
Interest Accrued
Total Amount Now Due

About this calculator

Calculate accrued interest owed on an overdue freelance or contractor invoice based on days late and your stated interest rate.

Frequently Asked Questions

How is late invoice interest usually calculated?

Most contracts specify an annual percentage rate that is divided by 365 to get a daily rate, then multiplied by the number of days the invoice is overdue.

Is charging interest on late invoices legal?

In most places yes, as long as the rate and terms were disclosed in your contract or invoice terms before the work began. Check local regulations for maximum allowable rates.

What's a typical late fee interest rate?

Freelancers commonly charge between 1% and 3% per month (roughly 12%-36% annually), but you should check what's customary and legal in your area.