Compare any two dates and distinguish calendar components from exact calendar-day totals.
Calculate with the Date Difference Calculator
Dates are validated as calendar components before calculation.
Date Difference Calculator results
How to use the Date Difference Calculator
- Enter the required calendar dates, times, or rule values.
- Choose the counting convention or mode where offered.
- Select Calculate or press Enter.
- Review the result, basis, and limitations before using it.
Worked example
The difference from 1 August to 2 August is one calendar day, or two counted dates when the end date is included.
Assumptions
Date-only calculations use the proleptic Gregorian calendar and ignore clock time. Elapsed-time calculations and selected-zone conversions state their time basis separately.
Limitations
- Inclusive counting adds one day to a nonzero date span.
- Calendar months are not treated as fixed 30-day periods.
Frequently asked questions
What date basis does the Date Difference Calculator use?
The result uses calendar dates unless the page explicitly describes elapsed time or a selected time zone.
Can daylight-saving time change calendar-day totals?
No. Date-only calculations use normalized UTC day numbers. Elapsed timestamp and time-zone calculations are explicitly handled separately.
Are entered dates stored?
No. Calculations run in your browser and the entered dates are not saved or sent anywhere.