Invoice Due Date Calculator

An invoice due date calculator adds payment terms (Net 15, 30, 45, 60, 90 or a custom number of days) to the invoice date to give the exact due date, and shows whether it is due in a set number of days, due today or overdue.

This calculator takes the invoice date and payment term and gives you the exact due date, plus a live status showing whether it's still upcoming, due today, or already overdue. "Net 30" and similar payment terms are everywhere on invoices, but the actual due date they imply isn't always obvious at a glance, especially when you're juggling many invoices with different terms.

Standard net terms (15, 30, 45, 60 or 90 days from the invoice date) cover most business arrangements; select custom for anything non-standard your contract specifies. The calculation is a straightforward date addition, but doing it correctly and consistently across dozens of invoices — rather than eyeballing a calendar each time — avoids the easy mistake of chasing payment too early or too late.

Use this when setting up a new customer relationship (agreeing terms upfront and knowing exactly what date that implies), when building a collections follow-up schedule (know precisely when an invoice crosses into overdue territory), or simply to double-check your own or a supplier's stated due date on an invoice.

The status line updates against today's date, so bookmarking this tool and re-checking it periodically for your open invoices is a quick, low-effort way to spot which accounts have quietly slipped into overdue territory before they've been chased — pairing that with the payment reminder generator turns the check into an actual follow-up in under a minute.