Months Between Dates Calculator
Compare two dates using complete calendar months, remaining days and average-length months.
What would you like to do next?
Measure a date span in calendar months
Select two dates in either order. The calculator identifies the earlier and later date, counts complete calendar months, reports leftover days and also divides total days by the average Gregorian month for a decimal comparison. Showing calendar and average-length views together prevents one hidden convention from being mistaken for the only definition of a month.
Choose the convention that matches the agreement
Months vary from 28 to 31 days, and end-of-month rules can differ across leases, billing, age, employment and legal deadlines. This screen does not include the ending date or apply a contract-specific convention. Confirm inclusivity, local rules and month-end handling before using the result for an obligation.
Frequently asked questions
Why are calendar and decimal months different?
Calendar months follow date boundaries, while decimal months use an average month length.
Can the dates be entered in reverse order?
Yes. The tool measures the absolute span between them.
Is the end date included?
No. The elapsed-day span excludes the ending date.