Months Between Dates Calculator

Enter two dates and see how many whole calendar months separate them, plus the days left over.

How do you calculate the months between two dates?

Move forward one calendar month at a time until you pass the second date, then count the remaining days. From 10 January 2025 to 19 March 2026 is 14 months and 9 days. Months are counted on the real calendar, so a month is never assumed to be 30 days.

Your result will appear here after you press Calculate.

How months between dates are counted

The calculator steps through the calendar one month at a time. A month counts as complete when the same day number in the next month has been reached or passed. Anything after that is reported as remaining days. This is the same arithmetic used by the Date Difference calculator, so the two tools always agree.

Why a month is not 30 days

February has 28 or 29 days, four months have 30 and seven have 31. Dividing by 30 gives 1.03 months for January and 0.93 for February, even though both are one calendar month. Contracts, notice periods and rental terms almost always mean calendar months, which is what the primary result shows.

Whole months compared with decimal months

Whole months plus remaining days answers questions like "how long has this contract run". Decimal months is an average-based approximation that is handy for spreadsheets and rough forecasting. The two will not always look the same, and that is expected.

Month-end examples

31 January to 28 February: 0 complete months, 28 days. February has no 31st.
31 January to 31 March: 2 complete months, 0 days.
29 February 2024 to 28 February 2025: 11 months, 30 days.
15 March to 15 March the following year: 12 complete months, which is 1 year.

Worked example

A lease starts on 10 January 2025 and ends on 19 March 2026. That is 14 months and 9 days, or 1 year, 2 months and 9 days, which works out at 433 total days and 61 whole weeks.

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Frequently asked questions

How many months are between two dates?

Count the calendar months that have fully passed, then count the days left over. From 10 January to 19 March is 2 months and 9 days, because January to March is two full months and 9 extra days.

Why is a month not always 30 days?

Calendar months run from 28 to 31 days. This calculator moves month by month through the real calendar instead of dividing by 30, so the answer matches how people read a contract or a notice period.

What is the decimal months figure?

It is the elapsed days divided by 30.436875, the average length of a month in the Gregorian calendar. It is useful for rough averages and spreadsheets, but it is an approximation, not a count of calendar months.

What happens with month ends like 31 January?

A month is complete only when the same day number is reached. 31 January to 28 February is 0 complete months and 28 days, because February has no 31st. 31 January to 31 March is 2 complete months.

What if I enter the dates the wrong way round?

You get the same size of gap with a note that the dates are reversed, and a Swap button to put them in order. This matches the Date Difference calculator.

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Calcadian calculators are for general planning and informational use. Please verify critical deadlines, legal, payroll, tax, HR, or official requirements with the relevant authorities or a qualified professional.