Months Between Dates Calculator

Enter a start date and an end date to see whole calendar months between them, split into years and leftover months, plus extra days after the last full month.

How it works

A calendar month is the same day-of-month in the next month, not 30 days. 15 January to 15 March is 2 months. When the target month is shorter, the day is clamped: 31 January to 28 February in a non-leap year counts as one full month (the anniversary cannot land on 31 February). Leftover days are what remain after that last anniversary. This is not “number of month names that appear on a wall calendar.”

Formula

Whole months = count of clamped month-anniversaries from start to end
Years / leftover months = whole months as 12 + remainder
Extra days = days after the last whole month

Worked examples

2024-01-15 to 2024-03-15 → 2 months
2023-01-31 to 2023-02-28 → 1 month

Useful notes

The same clamping rule as the age calculator, so 31 Jan → 28 Feb is one month.
If you need a day count instead, use Days Between Dates.

FAQ

Is a month always 30 days?: No. This tool uses calendar months. January to February is one month even when the day count is 28, 29 or 31.
What happens with 31 January?: The February anniversary is clamped to the last day of February. 31 January to 28 February (non-leap) is one whole month.
Can the result be negative?: Yes, if the end date is earlier than the start. The month count is signed so you can see the direction.

Related tools

See all Date & Time tools.