Date Calculator
Count the days between two dates, with business days, weeks, and a years-months-days breakdown that lands exactly on your end date. Leap years handled.
Inputs
Try an example
Result
- Days between the dates
- 20,843
- Business days
- 14,889
Monday to Friday. Public holidays are not excluded — subtract your own.
- Weekend days
- 5,954
Saturdays and Sundays
- In weeks and days
- 2,977 weeks, 4 days
- In years, months and days
- 57 years and 24 days
Whole calendar months first, then the real days left over
- Start date falls on a
- Sunday
- End date falls on a
- Thursday
| Unit | Amount |
|---|---|
| Days | 20,843 |
| Weeks | 2,977 (remainder 4) |
| Business days | 14,889 |
| Weekend days | 5,954 |
| Years, months, days | 57 years and 24 days |
- This is the number of days ELAPSED, so the end date is not itself counted. Switch the option above to count both dates.
- Business days are Monday to Friday, per 5 CFR § 610.111. No holiday calendar is applied — federal and state holidays differ, observed dates shift when one falls at a weekend, and none of it applies outside the United States.
- Whole calendar dates only: no time of day, no timezone and no leap seconds. A leap second adjusts a clock rather than a calendar and never adds a day.
Frequently asked questions
Should I count the end date or not?
It depends what you are counting. "How many days from Monday to Tuesday" is one day if you mean time elapsed, and two if you mean how many days are involved. A hotel charges for nights, so it bills the elapsed count; a deadline stated as "within 30 days" and a jury summons usually count both endpoints. This calculator defaults to elapsed days, because that is what subtracting one date from another gives, and offers the inclusive count as an explicit option rather than guessing.
How is a leap year decided?
A year is a leap year if it divides by 4, except that years divisible by 100 are not, unless they also divide by 400. So 1996 and 2024 are leap years, 1900 and 2100 are not, and 2000 and 2400 are. The century exception is the part that gets dropped, and dropping it produces an answer that is right about 96% of the time — wrong in precisely the cases someone reaches for a calculator to check. The U.S. Naval Observatory states the rule.
What counts as a business day here?
Monday through Friday, which is the basic federal workweek under 5 CFR § 610.111. Holidays are NOT excluded, and that is deliberate rather than an omission: there is no single holiday calendar that would be correct for everyone. Federal holidays differ from state ones, observed dates shift when a holiday falls at a weekend, and none of it applies outside the United States. Subtract your own holidays from the weekday count.
Why do the years-and-months figures not just divide the total days?
Because months are not a fixed length. The breakdown counts whole calendar months first and then measures the leftover in real days, so it lands exactly on your end date. Dividing 29 days by an "average month" of 30.44 gives 0.95 months, which is not a thing anyone means. From 31 January to 1 March 2023 the honest answer is one month and one day: one month after 31 January is 28 February, because the day clamps to the end of a shorter month, and one further day is 1 March.
Does the time of day or my timezone matter?
No. Everything here is whole calendar dates, with no time of day and no timezone. That is what stops a date shifting by one depending on where you are — the classic bug that moves a birthday across midnight. Leap seconds do not affect the answer either: a leap second adjusts a clock, not a calendar, and never adds a day.
Can I use dates before 1582?
Not here, and the reason is honesty rather than arithmetic. The Gregorian calendar was introduced in 1582, so applying it to earlier dates — a "proleptic" calendar — produces an exact number that does not match what was actually written down at the time, since those dates were recorded in the Julian calendar. The floor is set at 1600, safely after the reform, rather than offering a figure that looks authoritative and is historically misleading.
Sources
- Calendars — the Gregorian calendar and its leap-year rule — U.S. Naval Observatory, Astronomical Applications Department, retrieved 2026-08-13
- Julian Date formula — U.S. Naval Observatory, Astronomical Applications Department, retrieved 2026-08-13
- 5 CFR § 610.111 — Establishment of workweeks — Office of the Federal Register (eCFR), U.S. Government, retrieved 2026-08-13
- Leap Seconds — National Institute of Standards and Technology (NIST), retrieved 2026-08-13