Date Difference Calculator
Calculate the time between two dates in days, weeks, months, and years.
Select your dates
Choose a start and end date. Your result updates instantly.
By default the starting day is not counted. Dates stay in your browser.
Weeks and days are the remainder after full years and months.
How to use this calculator
- 1
Select a start date. This can be in the past or future.
- 2
Select an end date. The dates can be in either order.
- 3
Read the result. See total days, weeks, and a calendar breakdown. Tick “Include the end date” to count both days.
Example
From October 20 to December 1, 2026 there are 42 days — exactly 6 weeks. The calendar breakdown is 1 month, 1 week and 4 days.
With the end date included, the same range is 43 days.
How it is calculated
Each date is converted to a day number, and the answer is the difference between the two numbers. Leap days and month lengths are therefore exact, and the result does not depend on your time zone or on daylight saving changes, because no clock times are involved.
The starting day is not counted: October 20 to October 21 is 1 day. Tick “Include the end date” when both days should count, for example a hotel booking covering every night and morning, or a project that runs on both its first and last day.
The calendar breakdown takes whole months from the earlier date first, then counts the remaining days. If the start day does not exist in a month, its last day is used, so January 31 plus one month is February 28 (or 29 in a leap year).
Questions
Does the order of the dates matter?
No. If the end date is earlier, the calculator swaps them and tells you so; the number of days is always positive.
What is the difference between this and the Business Days Calculator?
This tool counts every calendar day. The Business Days Calculator counts only the weekdays you choose as working days.