Business Days Calculator
Business Days Calculator: free, instant and private. The day after the start date is the first counted day, which matches how leave and delivery estimates are usually read.
How the Business Days Calculator works
The Business Days Calculator takes Start date, End date, Holidays in between (one per line, YYYY-MM-DD) and returns the answer instantly — no button to hunt for, no page reload. The day after the start date is the first counted day, which matches how leave and delivery estimates are usually read. Payroll systems differ on whether Saturdays count — if yours does, add the Saturdays back or treat them as holidays.
Enter your own numbers to replace the example values; the result panel updates as you type. Everything runs in this single page, so nothing you enter leaves your device.
Formula used
count days after the start date that are Mon–Fri and not in the holiday list
| Symbol | Meaning |
|---|---|
| business days | Mon–Fri excluding your holidays |
| holidays | one ISO date per line — regional holidays vary |
| total days | every calendar day in between |
The day after the start date is the first counted day, which matches how leave and delivery estimates are usually read. Payroll systems differ on whether Saturdays count — if yours does, add the Saturdays back or treat them as holidays.
Inputs used: Start date, End date, Holidays in between (one per line, YYYY-MM-DD).
Worked example
Take the default example — start date of 2026-01-01, end date of 2026-01-31:
- businessDays: 21
- weekendDays: 9
- holidays: 0
- totalDays: 30
Frequently asked questions
- What formula does the Business Days Calculator use?
- It uses count days after the start date that are Mon–Fri and not in the holiday list, where business days is the Mon–Fri excluding your holidays; holidays is the one ISO date per line — regional holidays vary; total days is the every calendar day in between.
- Is the Business Days Calculator free?
- Yes. There is no signup, no usage limit and no watermark — the checker runs entirely in your browser.
- How do I read the result?
- The day after the start date is the first counted day, which matches how leave and delivery estimates are usually read. Payroll systems differ on whether Saturdays count — if yours does, add the Saturdays back or treat them as holidays.
- Does the Business Days Calculator store or send my data?
- No. Every calculation happens locally in the page, so the numbers you type are never uploaded or logged.
- Does it work on a phone and offline?
- Yes — the page is a single lightweight file that adapts to any screen size. Once it has loaded it keeps working without a network connection.