Date Difference Calculator
Find the number of days, weeks, and months between two dates.
Written by Anil Gautam · Updated
Does the day count include both dates?
The result counts the days you move forward from the start date to reach the end date, so only one of the two dates is included. From 1 January 2026 to 31 December 2026 the calculator shows 364 days, although the year has 365 days when both ends are counted. Add one whenever you need an inclusive count.
This matters for leave and travel. Leave from 10 March to 14 March 2026 shows as 4 days, while you are away for 5 calendar days. For a hotel stay with the same dates, 4 is the number of nights. Working Days Between Dates counts both the start and end dates and skips weekends and any holidays you list, which suits leave and project plans.
How are weeks and months worked out?
Weeks are days divided by 7, shown to two decimal places. Months are days divided by 30.437, the average length of a Gregorian month (365.2425 days divided by 12), so they are approximate. From 15 January 2026 to 15 April 2026 the calculator shows 90 days, 12.86 weeks and 2.96 months, even though the calendar says exactly 3 months.
Short and long months show the effect clearly: 1 February to 1 March 2026 is 28 days, or 0.92 months, while 1 July to 1 August 2026 is 31 days, or 1.02 months. A full year of 365 days reads 52.14 weeks and 11.99 months. For an age in whole years, months and days, use Age Calculator.
How are leap years and time zones handled?
Both dates are read as whole calendar days in UTC, so a daylight-saving change in your time zone cannot add or remove an hour and nudge the count. Leap days are counted when they fall in the range: 1 February to 1 March 2028 is 29 days. The start date opens on today's date and the end date on 31 December 2026.
To find the date a set number of days away, such as 90 days after a purchase, use Add or Subtract Days from Date.