Months Between Dates Calculator
Enter two dates to see the exact number of calendar months between them, plus the leftover days — using real month math, not days divided by 30.
How this is calculated
This calculator walks forward whole calendar months from your earlier date, clamping to the last day of a shorter month when the original day of month doesn't exist there (so January 31 plus one month lands on February 28, or the 29th in a leap year). Once it can't advance another full month without passing your later date, whatever's left over is counted in exact days. That's why it can't be reproduced by dividing total days by 30 — a fixed divisor ignores that months run 28 to 31 days long and gets the leftover-days figure wrong. For a pure day count instead, see Days Between Dates.
Frequently asked questions
Why isn't this just days divided by 30?
Because calendar months don't all have the same length — dividing total days by 30 (or 30.44) gives a rough estimate that drifts, especially over short spans. This calculator instead walks forward whole calendar months from your start date and only counts leftover days for whatever's left, so it matches how you'd count months by hand on a calendar.
Does it handle different month lengths correctly?
Yes. Each month you cross contributes its own actual length — 28, 29, 30, or 31 days — rather than an average. Going from January into February counts differently than going from January into April, exactly as it should.
What if the day of the month doesn't exist in the target month, e.g. Jan 31 plus 1 month?
The calculator clamps to the last day of the shorter month — January 31 plus 1 month lands on February 28 (or 29 in a leap year) — then counts any remaining days from there. So January 31 to March 1 comes out as 1 month, 1 day, not a distorted number from naive date subtraction.