Calculate the Number of Days Between Two Dates
Three calculators in one: the duration between two dates (days, weeks, months, business days), the date you get by adding or subtracting time, and an exact age from a date of birth.
- Business days
- Date + X days or months
- Exact age
- Free
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How to calculate the number of days between two dates?
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Pick a tab
Duration between two dates, adding or subtracting time from a date, or age calculation.
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Enter the dates
A start date and an end date, a date and a duration, or your date of birth. For a duration, you can include the end date in the count.
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Read the result
Number of days, resulting date and day of the week, or exact age: everything appears instantly, with no button to click.
Every date calculation in one place
Duration between two dates
In days, in weeks and days, and in years, months and days, with or without the end date.
Business days
The number of days from Monday to Friday in the period, to estimate a deadline or a number of working days.
Date plus or minus X days
Add or subtract days, weeks, months or years from a date, and get the resulting date and its day of the week.
Exact age
Your age in years, months and days, as a total number of days, and your next birthday: how many days away and on which day.
Counting the days between two dates: including the end date or not
By default, the calculator counts the gap between two dates: from Monday, March 2 to Friday, March 6, 2026, there are 4 days. If the last day counts too, as for a stay, time off or a rental from the 2nd to the 6th inclusive, you get 5 days. From January 1 to December 31, 2026, the gap is 364 days, or 365 if you include the end date. The result is also given in weeks and days (364 days is exactly 52 weeks) and in years, months and days, which is easier to read for long periods. Leap years are handled automatically: in 2028, February will have 29 days.
Business days, calendar days and deadlines
Business days (or working days) are the days a company normally works, usually Monday to Friday. Calendar days include every day of the week, weekends and holidays too. The calculator counts the days from Monday to Friday without removing public holidays: there are 261 of them in 2026, including 22 in March. Subtract the holidays that fall on a weekday yourself, since they vary by country and sometimes by state or region: in 2026, the 11 US federal holidays are all observed on weekdays, leaving 250 business days, while the 8 bank holidays in England and Wales leave 253. For a legal or contractual deadline, always check how it's counted: some deadlines are in calendar days, others in business days.
Adding days to a date and calculating an age
To find a due date, add a duration to a start date: March 1, 2026 plus 90 days falls on Saturday, May 30, 2026. Note that adding 3 months isn't the same as adding 90 days, because months don't all have the same number of days. You can also go back in time by subtracting days, weeks, months or years. For an age, the calculation starts from the date of birth: someone born on July 14, 1995 is 31 years, 2 months and 17 days old on October 1, 2026, which is 11,402 days. Their next birthday will fall on a Wednesday, in 286 days.
Frequently Asked Questions
How do I calculate the number of days between two dates?
Enter the start date and the end date in the duration tab: the number of days appears instantly, along with weeks, years, months and days, and business days. Turn on the option to include the end date if the last day counts too.
How many business days are there in a year?
In 2026, there are 261 days from Monday to Friday. In the US, the 11 federal holidays are all observed on weekdays that year, which leaves 250 business days; in England and Wales, the 8 bank holidays leave 253.
How do I calculate my exact age?
Enter your date of birth in the age tab: you get your age in years, months and days, the total number of days you've lived, and the date of your next birthday with its day of the week.
What date will it be in 90 days?
Choose the start date and add 90 days: the tool gives the resulting date and its day of the week. For example, March 1, 2026 plus 90 days falls on Saturday, May 30, 2026.
What's the difference between business days and calendar days?
Business days are the days a company works, usually Monday to Friday, excluding public holidays. Calendar days include every day: weekdays, weekends and holidays. A 30-calendar-day deadline is therefore much shorter than a 30-business-day one.