Days between dates
Count the days, weeks and business days between two dates, or add days to a date.
How to use the days between dates
- Choose “Between two dates” or “Add or subtract days”.
- Pick the dates, or a start date and a number of days.
- Read the result in days, weeks, months and business days.
About this tool
How many days until a deadline, how long since a date, or what date it will be 90 days from now: the two modes of this calculator cover all of them. The difference is shown in days, weeks, months and years, plus Monday-to-Friday business days.
By default the end date is not counted, which is how durations are usually measured. Turn on “include end date” to count both days, as you would when counting the days of a trip.
Counting days
Days = (End date − Start date) in calendar days
Calendar days are counted from midnight to midnight, so daylight saving changes never add or remove a day. Business days exclude Saturdays and Sundays but not public holidays.
Example
From January 1 to December 25, 2026 is 358 days, or 51 weeks and 1 day. 90 days after October 21, 2026 is Tuesday, January 19, 2027.
Frequently asked questions
Does it include the start and end date?
It counts from the start date to the end date, not counting the end date, like most duration calculations. Tick “include end date” to add one day.
Are public holidays excluded from business days?
No, holidays differ by country and state. Business days here exclude weekends only; subtract holidays yourself.
How many days are in a year?
365, or 366 in a leap year. Leap years are divisible by 4, except century years not divisible by 400. 2028 is the next leap year.
How many weeks is 100 days?
100 days is 14 weeks and 2 days.