How to Calculate the Days Between Two Dates
Count the days between two dates correctly — leap years included — and add or subtract days.
Counting days the simple way
To find the days between two dates, subtract the earlier date from the later one. The tricky part is that months have different lengths and February changes in leap years, so counting by hand is error-prone. A date calculator converts both dates to a day count and subtracts them for an exact result.
Inclusive vs exclusive counting
There’s a common ambiguity: does the span include both the first and last day? A plain difference counts the gap between the dates (exclusive). If you need to include both endpoints — for example, counting holiday days — add one to the total.
Adding and subtracting days
To find a future or past date, add or subtract a number of days from a starting date. This is how you work out deadlines (“30 days from today”), due dates and reminders. A date calculator rolls the months and years over correctly so you don’t have to.
FAQ
How do I find a date 90 days from today?+
Use the add/subtract mode of a date calculator: enter today’s date, set 90 days, and choose “add” to get the exact future date, with month and year rollovers handled.