Late Fee Calculator

Calculate interest or flat late fees on overdue invoices.

Days late45

Late fee$56.25

Total now due

$2,556.25

Late fees encourage on-time payment and compensate you for the cost of waiting. They are usually expressed as monthly interest (for example 1.5% per month), annual interest or a flat fee.

Late fees must be agreed in advance and comply with local laws, which may cap interest rates. Include your late-fee policy in your invoice terms.

Formula

Days late = Payment date − Due date
Monthly: Fee = Amount × Rate × (Days late ÷ 30)
Annual: Fee = Amount × Rate × (Days late ÷ 365)

Example

$2,500 paid 45 days late at 1.5% per month incurs about $56.25 in late fees.

Frequently asked questions

Can I legally charge a late fee?

Generally yes, if it was agreed in your contract or invoice terms in advance and does not exceed limits set by law in your state or province.

What is a typical late fee?

1–1.5% per month is common for business invoices; some businesses charge a flat fee instead.

How do I add a late fee to an invoice?

Add it as a fee line in the invoice generator, or create a new invoice referencing the original.