Date calculator — days between dates and business days
Count the days between two dates, get the business days (Monday to Friday) in between, add or subtract days, weeks, months, or years, and see how many days are left until a target date — all in your browser. No sign-up, no uploads.
Calculate dates
How it works
Four rules, all computed in this tab:
- Whole calendar days. The page converts each date to a UTC day number and subtracts — July 15 to August 17, 2026 is exactly 33 days, in any time zone, across any daylight-saving change.
- Business days walk the span. Each day between the two dates is checked: Monday to Friday counts, Saturday and Sunday do not, and both endpoints count when they are weekdays.
- Month and year math clamps to the end of the month. Adding one month to January 31 lands on February 28 (or 29 in a leap year) — the standard convention — and un-clamps on the next longer month (January 31 plus two months is March 31).
- "Days until" uses your device's current date. The count is the difference between today and your target date; dates in the past are reported as days ago.
Worked example: 2026-07-15 (a Wednesday) to 2026-08-17 (a Monday) is 33 days — 4 weeks and 5 days — and 24 business days (Monday to Friday). Adding 14 days to 2026-07-15 lands on 2026-07-29; adding one month to 2026-01-31 lands on 2026-02-28, because February has no 31st.
When do you need a date calculator?
Date math comes up in more places than people expect. Common situations:
- Project and delivery deadlines. "Add days to a date" is the core of lead-time planning: a 14-day production run starting today, a 45-day freight transit, a 30-day warranty window — the result date is what goes on the plan.
- Contract, notice, and billing periods. Notice periods, subscription renewals, rental agreements, and invoice windows are all date spans. The calculator is a convenience — always confirm period rules with the actual contract or terms.
- Business days for approvals and SLAs. "In 5 business days" means weekdays only. Counting the workdays between two milestones (or finding the date 10 business days out) is the everyday version of this.
- Planning and countdowns. "Days until" a trip, an event, a deadline, or a seasonal date — knowing the exact number makes planning concrete.
Limits
- Weekends only for business days. The business-day count excludes Saturdays and Sundays but has no public-holiday calendar — holidays are regional and employer-specific, so you subtract them yourself when they fall inside your span.
- Month and year arithmetic clamps. Adding months or years keeps your day number when the target month has it and clamps to the last day when it does not (Jan 31 + 1 month = Feb 28/29). That is the common convention, not a legal definition.
- Calendar dates only. There is no time-of-day and no time-zone conversion. For meeting times across zones, use the Time Coordinator.
- Not legal or financial advice. If a deadline, notice period, or billing date has legal consequences, verify it against the governing document and jurisdiction.
Frequently asked questions
How do I count the days between two dates?
The calculator reports the difference in whole calendar days: July 15 to August 17, 2026 is 33 days. If you need to count both endpoints (for example, how many calendar days a booking or stay spans), add 1 to the result — July 15 through August 17 inclusive is 34 days.
What counts as a business day?
A business day is Monday through Friday. Weekends (Saturday and Sunday) are excluded, and both the start and end date count when they fall on a weekday. There is no public-holiday calendar — see the holiday question below.
How does adding months work — does January 31 plus one month become February 28?
Yes. Month and year arithmetic keeps your day of the month when the target month has it, and clamps to the last day when it does not. January 31 plus one month is February 28 (or 29 in a leap year); plus two months it is March 31. February 29 plus one year is February 28 in non-leap years.
Does this calculator handle time zones or daylight saving?
It works with calendar dates only — no times of day, and no time-zone conversion. Day math is done on UTC calendar days, so the count is the same everywhere and daylight-saving changes can never add or remove a day. For meeting times across zones, see the Time Coordinator tool.
Is this date calculator free, and do you upload my dates?
Yes, it is free, and no — nothing you enter is uploaded anywhere. This is a static page: the calculation runs entirely in your browser tab, and your dates are never sent to a server, logged, or stored.
Why does the business-day count not include public holidays?
Public holidays are regional, employer-specific, and change every year, so no single calendar is "correct" for everyone. The honest default is a weekends-only count; check the holidays that apply to your country, state, or company and subtract them yourself when they fall inside your span.
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Part of Local Toolworks. Last reviewed: 2026-08-17.