Tools
Numbers & Dates
Days Between Dates
Count exactly how many days, weeks, or months fall between any two dates.
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