PaymentTermsCalculator

Invoice Due Date Calculator

Calculate any invoice due date — pick your start-date basis and term

Last reviewed 2026-08-14

Business days = weekends excluded. Federal holidays are not excluded.

Why the Start Date Matters

The most common source of invoice due-date disputes isn't the term length — it's which date the term counts from. "30 days" from the invoice date, from the delivery/completion date, and from the end of the invoice month (EOM 30) can produce due dates weeks apart for the same invoice. Always confirm the start-date basis in your contract or purchase order before assuming.

Related Calculators