Measure month-based duration without pretending every month has 30 days.
Calculate with the Months Between Dates Calculator
Dates are validated as calendar components before calculation.
Months Between Dates Calculator results
How to use the Months Between Dates 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
31 January plus one completed month reaches 28 February in a common year by month-end clamping.
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
- Fractional months divide remaining days by the length of the current partial month.
- Different fractional-month conventions can produce different results.
Frequently asked questions
What date basis does the Months Between Dates 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.