Date Difference Calculator

Days, weeks, months, years and business days between two dates

From

Days

Weeks

Months

Years

Business days

How it works

Date Difference Calculator — Days, weeks, months, years and business days between two dates. All processing happens in your browser — no upload, no signup, no email required. Free forever.

Last updated: 2026-05-06

Editor's note

Business days is where every "days between" calculator we tried fell apart. Some quietly assume US federal holidays, some assume none, some assume the user is in the UK — none of them tell you which calendar they used. We made a deliberate choice to keep the math simple and honest: working days equals total days minus Saturdays and Sundays. Regional holidays are not subtracted, and we say so out loud. A predictable number you can adjust beats a magic number you cannot audit.

The other thing we obsessed over: whether to count both endpoints. Half of finance teams want inclusive, half want exclusive, and the loudest arguments in invoicing come from that one-day gap. We default to exclusive of the start and inclusive of the end — the convention that matches "net-30" billing — and document it in the tips so you can add 1 when you need the other convention. No hidden toggle, no surprise.

About Date Difference Calculator

Counting days between two dates by hand is the kind of task that always takes ten minutes longer than it should — calendars on the wall, finger-counting across month boundaries, second-guessing whether to include the start date, the end date, or both. The date-difference calculator settles every one of those questions instantly. Type a From date and a To date and the result appears as Days, Weeks, Months, Years, and Business days, all computed from the actual calendar with leap years and 28/30/31-day months handled correctly.

Worked example: from 2026-01-01 to 2026-12-31 is exactly 364 days, which is 52 weeks, 11 months and 30 days, or 0 years 11 months 30 days when broken down. From 2026-01-01 to 2027-01-01 inclusive is 365 days — exactly one year. Business days exclude Saturday and Sunday automatically: from Monday 2026-04-13 to Friday 2026-04-17 is 5 business days, while the same five-day window starting on Friday 2026-04-17 counts only 3 business days because the weekend falls inside it.

The order of the dates does not matter — the calculator always returns the absolute difference, so swapping From and To gives the same answer. That makes the tool equally suitable for retrospective questions ("how long ago did I move in?") and prospective ones ("how many days until the project deadline?").

How to use Date Difference Calculator

Pick the From date using the first date picker.
Pick the To date using the second date picker.
Read all five outputs at once: Days, Weeks, Months, Years, and Business days.
Swap the dates if you accidentally entered them in the wrong order — the result is identical, so no action is required for absolute counting.
Toggle between past and future dates freely; the calculator never produces negative numbers.

Common use cases

Counting business days for a contractor invoice that bills net-30 from delivery.
Planning a 90-day product launch countdown from today's date.
Calculating tenure for an HR letter — years and months between hire date and today.
Working out how many days you have left on a visa or insurance policy.
Checking whether a refund window has elapsed by computing days since purchase.

Tips & common mistakes

Business-day counts exclude Saturday and Sunday but not public holidays — subtract those manually if your calendar uses them.
Months are not exact 30-day blocks. The calculator aligns the day-of-month, so 31 January to 1 March is 1 month and 1 day, not 'about 30 days = 1 month'.
For an inclusive count (counting both endpoint dates) add 1 to the day total — the default is exclusive of the start, inclusive of the end.
Daylight-saving transitions never affect the day count because we work in calendar dates, not seconds.

Frequently asked questions

Are weekends and holidays excluded from business days?

Weekends are excluded automatically (Saturday and Sunday). Public holidays vary by country and are not subtracted.

Why are months and years not always exact?

Months have 28–31 days. We compute calendar months by aligning the day-of-month, so going Jan 31 → Mar 1 is 1 month and 1 day, not '31 days = 1 month'.

Does the order of dates matter?

No. We always compute |To − From|, so swapping the two dates gives the same result.

Can I exclude national holidays from the business-day count?

Not directly — holiday lists vary by country, region, and year. After you get the business-day total, subtract the number of relevant holidays in the window manually for your jurisdiction.

How are months counted when the start and end days differ?

We align the day-of-month and borrow from the previous month if the end day is earlier. From 2026-03-15 to 2026-05-10 is 1 month and 26 days (March 15 → April 15 is one month, then April 15 → May 10 is 25 days, plus the borrow rule produces 26).

Does the tool work across the year 2000 or other century boundaries?

Yes. JavaScript date arithmetic uses the Gregorian calendar back to year 1 and forward indefinitely, so any pair of 20th- or 21st-century dates is handled correctly.

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