Invoice Due Date Calculator — Net 30, Net 60 & EOM
Turn agreed payment terms into a date you can put on your invoice. Choose a start date, count calendar days and review any weekend adjustment before copying the result.
Counts calendar days after your chosen start date. Weekends stay in the count. The optional Monday adjustment changes only the final date; public holidays are not checked.
Use the invoice date if that is your agreed starting point. For terms counted from receipt or delivery, choose that date instead.
Off by default. Turn this on only when the agreed payment terms allow it. Monday may still be a public holiday.
Invoice due date examples
These fixed examples use the same calculation as the tool. Try one to compare calendar-day counting, month-end terms and the optional weekend adjustment.
| Example | Start date | Before adjustment | Result | Try it |
|---|---|---|---|---|
| Net 30 from 1 March | ||||
| Net 15, weekends kept | ||||
| Net 15, weekend moved | ||||
| Month end + 30 calendar days | ||||
| Net 30 across leap-year February |
For example, 15 days after 17 October 2026 is Sunday 1 November. Enabling the weekend option changes only that result to Monday 2 November, which is 16 calendar days after the start.
Choose payment terms from your agreement. For jurisdiction-specific rules, consult official guidance such as GOV.UK’s payment-obligations page for the UK. This calculator does date arithmetic; it does not decide the legal deadline for a transaction.
How to calculate an invoice due date
First, check which date the payment period starts from. It might be the invoice date, the date the customer receives it or another date in your agreement. This calculator uses whichever start date you choose; it does not infer the agreement from an invoice.
For a Net term, it adds the selected number of calendar days after the start date. The start date is day zero, so Net 30 from 1 March 2026 gives 31 March 2026. Every date in between counts, including Saturdays and Sundays.
- Choose the start date specified by your payment terms.
- Select Net 7, 14, 15, 30, 45, 60 or 90, or enter custom calendar days.
- Keep the weekend adjustment off unless your agreement calls for it.
- Review the full result, then enter the agreed date in the invoice editor.
Net terms and end-of-month terms use different starting points
A month is not always 30 days long. Adding 30 calendar days to your chosen date can produce a different result from adding 30 days after that month ends. Choose the option that matches what you agreed, and use a full date on the invoice so the customer can check it.
| Option | Calculation used here |
|---|---|
| Same day (0 days) | Returns the chosen start date before any optional weekend adjustment |
| Net 15 / Net 30 / Net 60 | Adds exactly 15, 30 or 60 calendar days after the start date |
| End of month | Returns the final calendar date of the selected month |
| End of month + 30 | Finds that month’s final date, then adds 30 calendar days |
| Custom | Adds a whole number from 0 to 3650 calendar days |
Calendar days, weekends and public holidays
This tool does not count business days. It counts every calendar day, then optionally moves a final Saturday or Sunday result to Monday. The unadjusted date stays visible so you can see what changed.
Public holidays, bank processing times and local weekend patterns are not included. A Monday result may still be a holiday. The weekend option is a planning choice, not a rule that payment is automatically allowed later.
Use the result without changing your payment agreement
Copy the calculated date, check it against your agreement and enter it in Payment Due in the invoice editor. Opening the editor does not transfer the date automatically. The calculator does not read or change saved invoices.
The optional reminder dates are reference points three days before the result, on the result and seven days afterwards. They are calendar dates only: no messages are scheduled or sent, and no invoice is marked overdue.
If the wording is unclear, agree the starting point and counting method with the customer before relying on the result. Questions about legal deadlines, interest or enforcement need the rules for the particular transaction and jurisdiction.
Frequently asked questions
Does this Net 30 calculator count business days?
No. It adds 30 calendar days after your chosen start date, counting weekends. The optional Monday adjustment affects only the final result; it does not turn the count into 30 business days.
Is Net 30 the same as one month?
Not always. For example, 30 calendar days after 31 January 2028 is 1 March 2028. Month lengths vary, and a leap-year February has 29 days. This tool adds days rather than moving to the same numbered day of the next month.
What does end of month plus 30 mean here?
The calculator finds the last day of the start date’s month and adds 30 calendar days. From 12 January 2026, it starts that count at 31 January and returns 2 March 2026 before any weekend adjustment. Confirm that this matches your agreed EOM wording.
What if my invoice is due on receipt?
Choose the actual receipt date as the start and select Same day (0 days). The calculator cannot know when the customer received an invoice. Leave the weekend adjustment off unless your agreed terms allow a change.
Does it handle public holidays?
No holiday calendar is used. Only Saturday and Sunday can be moved by the optional weekend setting, and a Monday may still be a holiday. Check the applicable calendar and your agreement separately.
Will it send payment reminders?
No. It can show reference dates for planning reminders, but it does not schedule or send messages, collect payments, check whether an invoice is paid or determine a legal deadline.