Days Between Dates

Count exactly how many days, weeks, or months fall between any two dates.

Start Date

End Date

How it works

The formula

Days = JDN(end) − JDN(start)

Each date is converted to a Julian Day Number (JDN) — a continuous count of days since Jan 1, 4713 BC. Subtracting gives the exact difference.

Days in each month

Jan31

Feb28 / 29

Mar31

Apr30

May31

Jun30

Jul31

Aug31

Sep30

Oct31

Nov30

Dec31

Feb has 29 days in leap years (divisible by 4, except century years unless also divisible by 400).

Example

Jan 1, 2000 → Jan 1, 2025

25 calendar years

6 leap years (2000,04,08,12,16,20)

19 × 365 + 6 × 366

= 6,940 + 2,196 = 9,136 days