Free Tool

Late payment interestcalculator

Calculate interest charges and late fees on overdue invoices. Supports monthly rates, annual rates, and flat fees, so you know exactly what your clients owe.

Free to useMultiple fee structuresNo sign-up required

Late Payment Interest Calculator

Calculate interest and penalties on overdue invoices

One-time flat fee added on top of interest (common for small invoices)

When to charge late payment interest

Late fees can incentivize on-time payment, but they're not always the right approach. Here's when they make sense.

1

Include terms upfront

Late fee terms must be in your contract or invoice before work begins. Springing fees on clients after the fact is unprofessional and often unenforceable.

2

Keep rates reasonable

1-2% per month is standard. Anything above 2% per month may violate usury laws in your state. Check local regulations before setting your rate.

3

Send reminders first

Most late payments are accidental. The client simply forgot. Automated reminders (especially SMS with 98% open rate) resolve most cases before fees apply.

4

Reserve for chronic offenders

Apply late fees consistently for repeat offenders, but consider waiving them for first-time or otherwise reliable clients. Relationships matter.

5

Offer a grace period

A 5-7 day grace period after the due date shows good faith and gives clients with slow payment processing time to settle up.

6

Prevention beats penalties

Automated reminders prevent late payments. Late fees punish them after the fact. The best strategy uses both, but reminders do the heavy lifting.

Need help with the wording? Check out our invoice reminder email templates for professional follow-up messages at every stage. Or calculate your collection efficiency with our DSO calculator.

Frequently asked
questions

Prevent late payments
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ChaseBot sends automated SMS + email reminders before invoices go overdue, so you rarely need to calculate late fees at all.

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