Calculators

Days Between Dates

Days, months and years between two dates

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About this tool

The Days Between Dates calculator measures the gap between any two calendar dates and shows it four ways at once: total days, complete weeks, calendar months and calendar years. Project managers timing sprint windows, students counting days to an exam, and event planners counting down to a launch all need a quick, unambiguous duration that a plain calendar can't provide. Enter a start date and an end date — or click End today to fill in today's date — then click Calculate difference. Either date can come first: the numbers are always positive, and a line underneath says whether the end date falls before or after the start. Days are elapsed days, so the start date is not counted; add one if you need inclusive counting. Calendar months compare the month and year of the two dates and ignore the day of the month, and calendar years are whole multiples of twelve of those months. All calculation happens in your browser.

Why use it

  • Four Units at Once: Days, weeks, calendar months and calendar years are shown together from a single date pair, so you rarely need a second calculation.

  • Either Order Works: Enter the dates in any order. The tool reports the size of the gap and states whether the end is before or after the start, which is handy for working out how long ago something happened.

  • Elapsed-day Counting: Days are counted the way spreadsheets and programming languages do, excluding the start date. Add one when a contract counts both the first and last day.

  • End Today Shortcut: One click sets the end date to today, which makes 'how long since' and 'how long until' questions quick.

  • No Account Needed: Open the tool, pick two dates, read the answer, close the tab. There is no sign-up and no data retained between sessions.

How to use

  1. Enter the start date with the date picker
  2. Enter the end date, or click End today to use today's date
  3. Click Calculate difference
  4. Read the Days, Weeks, Calendar months and Calendar years tiles
  5. Check the line below, which says how many days the end is before or after the start

When it helps

  • Counting the number of days in a lease, employment contract, or notice period
  • Calculating how many days remain until a project deadline, product launch, or exam
  • Verifying a statutory period such as a 90-day warranty, a 30-day return window, or a 180-day visa stay
  • Checking how many weeks or months have passed since a milestone date
  • Measuring how long ago a historical event happened

Examples

Project span

Input

Start: 2025-01-15, End: 2026-05-07

Expected result

477 days · 68 weeks · 16 calendar months · 1 calendar year — end is 477 days after the start

Notice period

Input

Start: 2026-05-07, End: 2026-08-05

Expected result

90 days · 12 weeks · 3 calendar months · 0 calendar years

Decade gap

Input

Start: 2010-06-01, End: 2026-05-07

Expected result

5,819 days · 831 weeks · 191 calendar months · 15 calendar years

Tips

  • For contracts that count both the signing day and the expiry day, add 1 to the Days figure
  • Use ISO YYYY-MM-DD dates to avoid locale-based parsing surprises when typing
  • Rely on the Days tile for precise durations — calendar months ignore the day of the month
  • Copy the Days figure for use in spreadsheet DATEDIF or date-arithmetic formulas
  • Pair with the Business Days Calculator when weekends should not count

Frequently Asked Questions

Does the end date count in the total days?
No. The tool counts elapsed days, so January 1 to January 3 is 2 days. If you need inclusive counting, as in many leases and legal notices, add 1 to the Days figure.
What is the difference between calendar days and business days?
Calendar days count every day including weekends and public holidays. Business days exclude Saturdays and Sundays — and sometimes public holidays. This tool counts calendar days only; use the Business Days Calculator for Monday–Friday counts.
How are calendar months counted?
The tool compares the month and year of the two dates and ignores the day of the month. January 31 to February 1 therefore counts as 1 calendar month even though only one day has passed, and May 7 to August 5 counts as 3. Use the Days figure when you need precision.
Can I enter dates in MM/DD/YYYY format?
The date picker accepts any format your device's native picker supports. When typing manually, the ISO YYYY-MM-DD order avoids ambiguity, because MM/DD and DD/MM read differently in dates like 04/05/2026.
Can I get the result in hours or minutes?
No, the tool shows days, weeks, months and years. Multiply the Days figure by 24 for hours or by 1,440 for minutes — for example 90 days is 2,160 hours.
What happens if the end date is before the start date?
The figures stay positive and the line below the result says the end is that many days before the start date. Swap the dates if you prefer to read it the other way round.
How are weeks and years rounded?
Both are rounded down to whole units. Weeks are total days divided by 7, and calendar years are calendar months divided by 12, so 477 days shows as 68 weeks and 16 months as 1 year.

Explore the category

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Glossary

Calendar Day
Any day on the standard calendar including weekends and holidays. Calendar days are the simplest unit for measuring a date gap and form the basis for all other time-unit conversions.
Inclusive Date Range
A range where both the start and end dates are counted as part of the total. For example, January 1 to January 3 inclusive is 3 days, whereas exclusive counting gives 2 days.
ISO 8601
An international standard for representing dates and times in the format YYYY-MM-DD. Its unambiguous ordering eliminates the US vs European day/month confusion that causes date parsing errors.
Epoch Time
A count of seconds (or milliseconds) since January 1, 1970 00:00:00 UTC. Many programming environments internally convert calendar dates to epoch values before subtracting them to find a duration.
Business Day
A weekday (Monday through Friday) that is not a public holiday. Business-day counts are commonly required in legal notice periods, financial settlement windows, and project scheduling.
Duration
The length of time between two points. In ISO 8601 notation, a duration is expressed as P followed by years (Y), months (M), weeks (W), and days (D) — for example P1Y3M22D for one year, three months, and 22 days.
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