Invoice Due Date Calculator

What this calculator does

The Invoice Due Date Calculator works out when an invoice is due based on the invoice date, the chosen payment terms, and whether you want to count calendar days or business days. It also gives you a reminder date so you know when to follow up before the deadline arrives.

Why it is useful

Freelancers, agencies, accountants, and finance teams often need to check due dates quickly while preparing invoices, reviewing accounts receivable, or planning reminder emails. This tool keeps those calculations consistent across common terms like Net 7, Net 15, Net 30, and custom agreements.

Calendar days vs business days

Calendar-day mode counts every day on the calendar, including weekends. Business-day mode skips Saturdays and Sundays, which can be useful when your contract or internal policy tracks due dates by working days instead of all days.

Reminder planning

Use the reminder lead time to decide how many days before the due date you want a follow-up prompt. The calculator applies the same counting mode to the reminder date, and it will not place a reminder before the invoice date itself.

Important limitation

Business-day calculations in this tool exclude weekends only. They do not include country-specific public holidays, bank holidays, or custom office closures, so double-check the result if your payment policy depends on those dates.