Days Between Dates Calculator

Choose a start date and an end date. The default calculation counts from the start date up to, but not including, the end date.

Enable Include the end date when both selected dates should belong to the total. Use Swap dates to reverse the entries without retyping them, or Reset to return to today and a date seven days later.

The result separates total calendar days, Monday-to-Friday weekdays, Saturdays and Sundays, exact whole weeks, and decimal month and year equivalents.

A date interval needs a boundary rule. With the end date excluded, July 11 to July 18 is seven days because the count covers July 11 through July 17.

Including the end date adds the final calendar date, so the same selection becomes eight days. When both inputs are the same, the exclusive result is zero and the inclusive result is one.

Neither convention is universally correct. Bookings, legal notices, project plans, subscriptions, and travel schedules can define their boundaries differently, so use the rule required by the real situation.

Calendar days include every counted date. The weekday result counts Monday through Friday, while weekend days count Saturday and Sunday.

The weekday figure is often called a business-day or working-day count, but this calculator removes weekends only. A public holiday that falls on Monday through Friday remains in the weekday total.

Holiday-aware calculations need a location, holiday calendar, observed-day rules, and sometimes organization-specific closures. Those inputs are deliberately outside this global date calculator.

The inputs represent civil calendar dates rather than moments on a clock. The engine converts each validated YYYY-MM-DD value to a Gregorian day number and subtracts those day numbers.

It does not divide the milliseconds between two local-midnight Date objects. That distinction matters because a local day can contain 23 or 25 elapsed hours when a region changes its clocks.

As a result, two adjacent calendar dates remain one calendar day apart even when a daylight-saving transition occurs between them.

The Gregorian calendar inserts February 29 in years divisible by four, except century years not divisible by 400. The day-number calculation applies that rule automatically.

Crossing a month or year boundary does not require a fixed 30-day month assumption. The exact calendar-day result is based on the actual dates, including February and leap days.

The average-month result is separate. It divides the exact day total by the mean Gregorian month length only to provide a rough decimal comparison.

A week always contains seven calendar days, so the whole-weeks-plus-days breakdown is exact. Ten days becomes one complete week plus three days.

Calendar months vary from 28 to 31 days, and years contain 365 or 366 days. The calculator therefore labels months and years as average equivalents rather than exact calendar components.

Use the exact day or week result for deadlines and schedules. Use average months and years only when a broad proportional comparison is useful.

The calculator accepts an end date earlier than the start date. The calculation engine preserves that direction internally, and the interface clearly states that the end date is earlier.

Weekday, weekend, week, month, and year details are displayed as the absolute size of the interval so the breakdown remains easy to read.

Use Swap dates when the dates were entered in the wrong order or when you want to compare the same interval in the opposite direction.

A mathematically correct day count can still be the wrong operational answer when the underlying rule is unclear.

Before relying on a result, determine whether the start date counts, whether the end date counts, whether weekends are working days, whether holidays are excluded, and whether a deadline ends at midnight or at a specific time.

For contracts, visas, employment notices, benefits, taxes, court filings, or regulated deadlines, follow the governing document and applicable professional guidance rather than assuming a general calculator defines the rule.

Most one-day disagreements come from including or excluding the end date. Larger differences often come from removing weekends, public holidays, or both.

A time-duration calculator can also differ from a date-only calculator because it measures exact elapsed hours and may reflect daylight-saving changes.

Compare the boundary rule, weekend rule, holiday treatment, calendar system, and whether times of day are present before deciding that either result is incorrect.

The selected dates and results remain in the browser. The tool does not upload the dates, create an account record, or place the values in a public share URL.

The default dates are derived from the device's local calendar after the page hydrates. Changing or swapping dates does not request location access.

Reset returns to the current local date and a date seven calendar days later.