Date Difference Calculator is a free tool that tells you how many days, weeks, months and years there are between two dates, and how many of them are working days. It can also add or subtract days, working days, weeks, months or years from a date, for deadlines, notice periods and countdowns. Everything is calculated on your device.
How to count the days between two dates
- Choose the start date, or click Today.
- Choose the end date.
- Read the result in years, months and days, with totals in days, weeks, hours and working days below.
Tick Count the end date too when both the first and last day should count, as for holidays and hotel-style counts of days. Tick Include times to count hours and minutes as well.
How to add days to a date
- Choose Add or subtract.
- Pick a date, then enter a number and a unit, such as 90 days or 10 working days.
- The resulting date appears with its day of the week.
Examples
- Notice period: 1 month from 31 January is 28 February (29 in a leap year), the last day of the shorter month.
- Payment terms: “30 days from invoice” counts calendar days; “10 working days” skips Saturdays and Sundays.
- Age: from a birth date to today gives an exact age in years, months and days.
- Countdown: from today to a wedding, exam or launch date tells you how many days and weeks are left.
How the calculation works
Whole months are counted first, the way a calendar reads (15 March to 15 May is 2 months), then the remaining days. Leap years are included. Daylight saving changes don’t affect the result: a day is always one calendar day. Public holidays vary by country, so working days count every Monday to Friday.
Developers can copy the result as an ISO 8601 duration such as P1Y2M3D; theISO 8601 Converter explains any duration. To convert a date to Unix time, use theUnix Timestamp Converter.
Frequently asked questions
Does it count the end date?
Not by default: from 1 to 2 September is 1 day. Tick “Count the end date too” when both days should count, such as for a holiday from Monday to Friday (5 days).
How are months counted?
Like a calendar: from 15 January to 15 March is exactly 2 months, whatever the number of days in between. Adding a month to 31 January gives 28 February (or the 29th in a leap year), the last day of the shorter month.
Are public holidays excluded from working days?
No. Holidays differ by country and region, so working days count every Monday to Friday. Subtract any holidays in your range yourself.
Can I calculate someone’s age?
Yes. Enter the date of birth as the start date and today as the end date; the years, months and days are the exact age.
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