Math calculator
Date Difference Calculator
Find the number of calendar days between two dates.
How this calculation works
Calendar-day difference = |end date − start date| ÷ 86,400,000 milliseconds Use the calculator above to enter your values. Inputs are checked before a result is shown, and calculations run locally in your browser.
January 1 to January 8: 7 calendar days.
March 1 to March 31 in a non-leap year: 30 calendar days.
December 30 to January 2: 3 calendar days.
Frequently asked questions
How does the date difference calculator work?
Calendar-day difference = |end date − start date| ÷ 86,400,000 milliseconds
What is an example?
January 1 to January 8 is 7 calendar days (8 days if counting both dates inclusively).
Can I enter decimal values?
Yes. Enter decimal values where appropriate. The calculator checks required inputs and displays a readable result.
Are results rounded?
Results are formatted for readability. Check the displayed formula and units when using the result.
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