Months between dates
Work out how many complete calendar months are between two dates — useful for ages, tenure, warranty periods or subscription lengths.
Result
Complete months
How to use this calculator
- Enter the start date.
- Enter the end date.
- Read the number of complete months between them.
Assumptions
- Counts whole completed months only — a period of, say, 3 months and 10 days is reported as 3 months, not 3.3.
Technical details: what the fields mean
- Start date
startDate - The earlier date.
- End date
endDate - The later date.
Methodology
Counts complete calendar months — a month only counts as complete once the end date's day-of-month reaches or passes the start date's day-of-month.
Worked example
15 Jan 2026 to 20 Apr 2026
Inputs: startDate=2026-01-15, endDate=2026-04-20
Result: 3 complete months
Practical guidance
- For a precise months-and-days breakdown, use this for the whole-months figure and the days-between-dates calculator for the remainder.
Common mistakes
- Approximating months as days ÷ 30, which drifts noticeably over several months since real months vary from 28 to 31 days.
FAQs
How many months between two dates?
This counts complete calendar months — a month only counts once the end date's day-of-month has been reached.