Late Payment Fee Calculator

Calculate days overdue, late fee amount, and total payable balance.

Invoice amountFlat feeInterest % (monthly)

Due dateCurrent date

Days overdue

Fee amount

$25

Total owed

$2,525

Reminder email: Your invoice is now 20 days overdue. Updated balance: $2,525 including late fee.

How to interpret results

Use either flat fee or monthly interest, then align wording with your invoice terms and local rules.

Use output as a decision support baseline. Re-run this tool whenever scope, utilization, or tax assumptions change.

An invoice overdue by 20 days at 1.5% monthly can produce a modest but clear penalty.

Swap your own assumptions to create a quote-ready number or policy clause.

Use your contract terms and relationship context.

Set sustainable hourly and day rates from your real utilization and costs.

Create clean invoices quickly without logging in.

Draft clear contract terms from practical project inputs.

A practical framework to price for income, tax, overhead, and utilization.

Choose the model that matches your service and risk profile.

Set a tax reserve percentage with less guesswork.

MVP placeholders for ethical monetization: premium templates, sponsored recommendations, and newsletter conversion.

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Contextual recommendations for accounting, invoicing, or legal providers.

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