Months Between Dates Formula Explained, With Examples
Every months between dates result comes from one formula. Once you understand what goes into it, you can sanity-check any figure you are given, whether by an employer, a bank, a teacher or another website.
The formula
Months = year difference × 12 + month difference, minus 1 if the end day is earlier.
What each input means
- Start date: the value you enter in the calculator.
- End date: the value you enter in the calculator.
Example
For example, with these inputs:
- Start date: 15 Mar 2024
- End date: 5 Oct 2026
the calculator returns:
- Complete months: 30 months
Why it matters
Dates and durations matter for notice periods, leave planning, project deadlines and contracts. Counting days on a calendar is slow and easy to get wrong, especially across months of different lengths.
When sharing dates internationally, write the month as a word to avoid confusion between day-month and month-day formats.
Age is calculated in completed years, months and days. Someone born on 29 February is usually treated as turning a year older on 28 February or 1 March in non-leap years, depending on the rule being applied.
Time durations are easier to handle in minutes. Convert each time to minutes after midnight, subtract, then convert back to hours and minutes, adding 24 hours for shifts that run past midnight.
Related calculations
- Age Calculator: Calculates exact age in years, months and days.
- Days Between Dates Calculator: Counts days between two dates.
- Add Days to a Date Calculator: Finds the date a number of days after another date.
- Subtract Days from a Date Calculator: Finds the date a number of days before another date.
Use the Months Between Dates Calculator to plug in your own numbers.
Run your own numbers: Months Between Dates Calculator