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Late Payment Interest Calculator

Estimate late payment interest and optional fixed fees on overdue invoices to support accounts receivable follow-up and collections planning.

This calculator is for estimation only and does not provide legal or financial advice. Late payment fees and interest may depend on your contract, jurisdiction, and local regulations.

Invoice and late payment details

Enter the invoice amount, due date, payment date, annual interest rate, and optional fixed late fee to estimate overdue interest.

Fixed late fee applies only when the invoice is overdue.

This calculator is for estimation only and does not provide legal or financial advice. Late payment fees and interest may depend on your contract, jurisdiction, and local regulations.

Calculate late charges to see days overdue, interest, fees, and total amount due.

What is late payment interest?

Late payment interest compensates a business when a customer pays after the due date. It is usually expressed as an annual percentage rate applied to the unpaid invoice balance for each day the invoice remains overdue.

How overdue invoice interest is calculated

A common approach is simple daily interest: invoice amount × annual rate × days overdue ÷ 365. Fixed late fees may be added separately when permitted by your contract.

When to use late fees carefully

Not every jurisdiction or contract allows interest and penalty fees. Disclose terms upfront, apply fees consistently, and confirm legal limits before invoicing late charges to protect customer relationships and compliance.

Improve collections with Arrexia

Arrexia tracks overdue invoices, automates payment reminders, and helps finance teams follow up before balances age—reducing the need to recover late payments through interest and fees.

Reduce overdue invoices before late charges add up

Use automated reminders, aging visibility, and consistent follow-up to improve collections with Arrexia.