How do you count working days between dates?

Both the start date and the end date count if they are weekdays and not holidays. That matches Excel NETWORKDAYS. Weekends are Saturday and Sunday.

When is a Net 30 invoice due?

Net 30 is 30 calendar days after the invoice date (the invoice date is day 0). An invoice dated Friday, August 28, 2026 is due Sunday, September 27, 2026 on the calendar. If you need the due date on a business day, the next weekday is Monday, September 28. Labor Day 2026 is Monday, September 7, so it does not move that example.

Is Net 30 calendar days or business days?

Most trade terms — Net 15, Net 30, Net 45, Net 60 — mean calendar days. The invoice mode on this page uses calendar days, with an optional toggle to roll a weekend or US federal observed holiday forward to the next business day. Add / subtract is different: it uses Excel WORKDAY (business days only). Read your contract.

Which holidays are used?

Optional US federal observed holidays for 2025, 2026, and 2027 from the OPM schedule (5 U.S.C. 6103), including in-lieu Fridays and Mondays when a holiday falls on a weekend. This is not a guarantee a bank or counterparty is closed. You can add custom dates.

Business Days Calculator — Net 30 Due Date & Working Days

Q: Is this legal advice?

No. This is calendar math, not legal, payroll, SLA, or collections advice. Holidays are US federal observed dates, not a promise that any office is closed.

Start date

End date

Holidays

Skip US federal observed holidays, 2025–2027

Dates follow the OPM federal holiday schedule (5 U.S.C. 6103), including in-lieu Fridays and Mondays. Federal observed is not a guarantee a counterparty, bank, or court is closed. In invoice mode these dates only move the due date when “due on business days only” is on.

Custom holiday (optional)

Result

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How the days are counted

Between dates includes both ends when they are working days — the same rule as Excel NETWORKDAYS. A Monday-to-Friday week is 5 business days. Friday to the next Friday is 6.

Add / subtract treats the start date as day 0, like Excel WORKDAY. Add 1 to a Friday and you land on Monday, unless Monday is a holiday.

Invoice / Net 30 uses calendar days, which is how most trade terms are written. Invoice dated Friday, August 28, 2026 plus 30 calendar days is Sunday, September 27, 2026. Turn on “due on business days only” and that Sunday moves to Monday, September 28. Labor Day 2026 is Monday, September 7 — it sits inside the 30 days but does not change a Sunday due date.

Weekend means Saturday and Sunday. There is no half-day, no Saturday-working schedule, and no state holiday pack in this version.

Worked example (business days)

Invoice dated Friday, August 21, 2026. Add 15 business days with federal observed holidays on. Labor Day 2026 is Monday, September 7. The due date is Monday, September 14, 2026. With holidays off, it would be Friday, September 11.

Federal observed holidays used here

Copied from the OPM year tabs for 2025–2027. Inauguration Day 2025 is the same date as MLK Day and is DC-area only, so it does not add a second nationwide off-day.

Observed	Holiday	Year

FAQ

How many working days between two dates?

Count weekdays from the start through the end, then subtract any holidays you have turned on. Both dates count if they are working days.

When is a Net 30 due date if the invoice is dated Friday?

Add 30 calendar days. Invoice dated Friday, August 28, 2026 is due Sunday, September 27 on the calendar. If payment is only accepted on a business day, the next weekday is Monday, September 28. Labor Day 2026 (Monday, September 7) is already in the table; it does not push that particular due date.

Do you skip US bank holidays?

The holiday toggle skips US federal observed dates from OPM, which is the usual nationwide list. Banks, courts, and private offices can differ. Add a custom chip if your counterparty is closed on another day. In invoice mode they only change the due date when “due on business days only” is checked.

Is Net 30 the same as adding 30 business days?

No. Net 15 / Net 30 / Net 45 / Net 60 are almost always calendar days. Use Invoice / Net 30 for that. The Add / subtract mode (and the “Net 30 business days” preset) is Excel WORKDAY — useful for SLAs, not for reading an invoice.

Is this legal advice?

No. Calendar math only. Not legal, payroll, SLA, or collections advice. Holidays are US federal observed dates from OPM, not a filing deadline and not a guarantee that any office is closed.

This calculator does calendar math. It is not legal advice, not a filing deadline, and not a guarantee that any office is closed. Holidays are US federal observed dates (OPM / 5 U.S.C. 6103). Confirm holidays and payment terms with your counterparty. Dates stay in this browser. No account.