Invoice Payment Calculator: Due Date from Any Net Term
This invoice payment calculator works out the payment due date for any net term — Net 10, Net 15, Net 20, Net 30, Net 45, Net 60 or Net 90 — or a custom day count. Enter the invoice date, pick whether the term runs from the invoice date, the delivery date, or the end of the invoice month, and choose calendar or business days. The result is the exact date the payment is due.
Payment Due Date Calculator — Calendar or Business Days
In calendar-day mode the payment due date is simply the start date plus the term. In business-day mode weekends are skipped (federal holidays are not). Use business-day mode only when your contract explicitly says "business days" — most net terms are calendar days by default.
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.
Frequently Asked Questions
How do I use an invoice payment calculator?
Enter the invoice date, choose the start-date basis (invoice, delivery, or end of month), pick the net term, and the calculator returns the payment due date.
How do I calculate a payment due date?
Payment due date = start date + term days. In business-day mode weekends are excluded from the count.
What if my invoice does not state a start-date basis?
Default to the invoice date unless your contract or PO specifies delivery date or end-of-month (EOM) terms.