Date calculator
Calculate the number of days between two dates. Includes weeks and months breakdown with step-by-step work.
How to calculate days between dates
Subtract the earlier date from the later date, accounting for different month lengths (28–31 days) and leap years (every 4 years, except centuries not divisible by 400).
Common date intervals
1 week = 7 days. 1 month ≈ 30.44 days (average). 1 year = 365 days (or 366 in leap year).
90 days ≈ 3 months. 180 days ≈ 6 months. 365 days = 1 year.
Leap year rules
A year is a leap year if: divisible by 4, except centuries (divisible by 100) are not leap years, unless also divisible by 400. So 2000 was a leap year, 1900 was not, 2024 is a leap year.
Frequently asked questions
Does this count the start date?
This calculator counts the days between the two dates (exclusive of start, inclusive of end). January 1 to January 2 = 1 day.
How many days are in each month?
Jan: 31, Feb: 28/29, Mar: 31, Apr: 30, May: 31, Jun: 30, Jul: 31, Aug: 31, Sep: 30, Oct: 31, Nov: 30, Dec: 31.