Invoice Due Date Calculator
Saturday, October 10, 2026
Payment is due 30 days after the invoice date.
- Due date
- 2026-10-10
- Days remaining
- 30
How this is calculated
Payment terms are counted in calendar days from the invoice date, not business days, so net thirty means thirty days later including weekends and public holidays. That sounds obvious until a month boundary is involved: an invoice issued on the thirty-first of January under net thirty falls due on the second of March in a normal year and the first of March in a leap year, and getting that wrong by a day is the difference between a polite reminder and an unenforceable late fee. This tool counts the days for you and tells you how many are left, or how many have passed if the date has already gone by. Dates are handled in UTC throughout, so the answer does not change depending on the time of day you happen to open the page or the timezone you are sitting in.
Worked example
September has thirty days, so thirty days after the first of September is the first of October. If today were the fifteenth of September the tool would also show sixteen days remaining, counting from today rather than from the invoice date.
Inputs: Invoice dated 1 September 2026, net 30 terms
Result: Due Thursday, 1 October 2026
What this assumes
- Payment terms are counted in calendar days, not business days. Weekends and public holidays are included.
- Days remaining are counted from today in UTC, so the figure does not shift with your local time of day.
- Net 0 means payment is due on receipt.
Questions
- Does net 30 mean thirty business days?
- No. Net 30 means thirty calendar days from the invoice date, weekends and holidays included. If you intend business days you must say so explicitly in the contract, because the default reading is calendar days.
- Should terms run from the invoice date or the delivery date?
- Whatever your contract says. Invoice date is the common default, but some clients pay from receipt of goods or from the end of the month in which they were invoiced. Agree it in writing before you send the first invoice, not after the first late payment.
- What happens if the due date is a weekend?
- The debt is still due that day. Many clients will pay the next working day, and most freelancers treat that as normal rather than late, but strictly the obligation falls on the date itself.