Date calculator
Find how many days separate two dates, or which date you reach after adding or subtracting a duration.
Sealed on this device
Runs in your browser. Nothing is uploaded.
Sealed
Dates
Counts the first and the last day, as in “Monday to Friday inclusive” (5 days).
Weekend days are skipped. Years, months and weeks are added first.
Adding months keeps the same day of the month. When that day doesn’t exist, the last day of the month is used: 31 January + 1 month = 28 February (29 in a leap year).
Used for business days. Public holidays are not taken into account.
Result
- Days between the dates
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- In weeks and days
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- In years, months and days
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- Business days
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- In hours
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- Result date
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- ISO format
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- Days from the start date
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How it works
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Choose a calculation
Count the time between two dates, or add or subtract a duration from a date.
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Pick the dates
Use the calendar or type the dates. “Today” fills in the current date in one click.
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Read the result
See the total in days, weeks, months and business days, or the date you reach with its day of the week.
Frequently asked questions
How many days are there between two dates?
Subtract the start date from the end date. By default the start day counts and the end day doesn’t, so from 1 to 2 January is 1 day. Tick “Include the end day” to count both, as in a hotel stay or a leave request from Monday to Friday inclusive.
What happens when I add a month to 31 January?
You get the last day of February: 28 February, or 29 in a leap year. Adding months keeps the same day of the month, and when that day doesn’t exist, the last day of the month is used.
How are business days counted?
Every day except the weekend days you choose: Saturday and Sunday, Friday and Saturday, Friday only or Sunday only. The default follows the usual weekend of your region. Public holidays vary by country and region, so they are not removed.
Are leap years taken into account?
Yes. A year is a leap year when it is divisible by 4, except century years that are not divisible by 400. So 2000 and 2024 are leap years, but 1900 and 2100 are not.
Can daylight saving time change the result?
No. The calculator counts whole calendar days, without clock times, so a 23 or 25 hour day still counts as one day. The total in hours is simply the number of days multiplied by 24.
How are years, months and days counted?
Whole months are counted first from the start date, then the remaining days. From 31 January to 1 March 2026 is 1 month and 1 day, because 31 January + 1 month is 28 February.