FREE TOOL · LOCAL CALCULATION

Calculate overdue invoice days and the estimated balance

Estimate days overdue, simple interest, and the updated balance. Then copy a reminder that asks for a concrete date without invented threats.

Updated August 1, 2026

Invoice details

Use rates and fees only when agreed in writing and allowed. The calculator does not determine what you may charge.

ESTIMATED STATUS

Invoice overdue
Days overdue30
Estimated simple interest$0.00
Interest + fee$0.00
Estimated balance$1,500.00
Interest per day$0.00

Suggested reminder

Hi [name], I am following up on invoice [number] for $1,500.00, due on Jul 2, 2026. It is now 30 days overdue. Could you confirm the expected payment date or let me know whether a detail is blocking processing?

Amounts and dates are calculated on this device. They are not sent or stored.

01 · FOLLOW UP WITH FACTS

Turn the calculation into a verifiable follow-up

1. Verify

Check the balance, currency, due date, and whether payment already arrived.

2. Calculate

Use only the rate, fee, and grace period written into the agreement.

3. Ask

Request a payment date or the administrative detail blocking processing.

4. Document

Record replies, promises, partial payments, and the final close.

FREE SAMPLE · 10 MESSAGES

Download payment reminders ready to adapt

Leave your email to receive ten collection messages. No payment or subscription will start.

FAQ

Frequently asked questions

Does the calculator decide what interest I can charge?

No. It only applies the values you enter. Review the contract and applicable rules before adding fees.

Does it use compound interest?

No. The estimate uses daily simple interest and adds an optional flat fee.

Does PDF Club save the amounts?

No. The calculation stays in the browser and the form sends only your email and topic interest.