Months Between Two Dates Calculator

The calculator counts the number of complete calendar months from your start date to your end date. It then calculates any remaining days beyond those full months, plus total days, total weeks, and decimal years as additional context.

This happens when the day of the start month is later in the month than the day of the end month. For example, from January 31 to December 30 is only 10 complete months and 30 days, not 11 full months, because the 31st has not yet been reached in December.

Checking this option adds one extra day to the calculation, counting the end date itself as part of the span. This is useful when you need to count both the start and end days inclusively — for example, for billing periods or project durations.

No. The calculator automatically determines which date is earlier and which is later, so you can enter them in any order and still get the correct result.

After counting all complete calendar months, the leftover portion that doesn't fill another full month is expressed as remaining days. For instance, 3 months and 15 days means there are 3 full months plus 15 extra days between the two dates.

Yes. The calculator uses JavaScript's native Date object, which fully accounts for leap years (February 29) and the varying lengths of different months, so your results are always accurate regardless of the year.

Decimal years expresses the total time span as a fraction of a year. For example, 6 months is approximately 0.5 years. This is calculated by dividing the total number of days by 365.25 to account for leap years over time.

Total weeks is simply the total number of days divided by 7, shown as a decimal. For example, 30 days equals approximately 4.29 weeks.