Age in Months Calculator

Find an age in total whole months plus leftover days from a birth date to any reference date.

Independently verified for accuracy

Calculator by Toolsloft ↗
Age in months
78 months, 0 days

Find an age in total whole months, plus the leftover days, from a birth date to a chosen date. Parents often track a baby in months, and this gives the exact figure with correct month lengths and leap years. Defaults to counting up to the date you choose.

How this is calculated

The tool counts whole calendar months from the birth date, then measures the leftover days to the reference date. Total months are the whole years times twelve plus the extra whole months, so six years and six months reads as 78 months.

How to use

  1. Enter the birth date.
  2. Enter the date to measure to.
  3. Read the age in whole months and leftover days.

Examples

  • Six and a half years: 2020-01-15 to 2026-07-15 = 78 months
  • A newborn: 2026-01-31 to 2026-03-01 = 1 month, 1 day
  • A leap birthday: 2024-02-29 to 2025-02-28 = 12 months

FAQ

How do I work out age in months?
Count each whole month from the birth date to today, then add the leftover days. The tool does this and also gives the running total in months.
Why must the birth date come first?
Age counts forward from birth, so the reference date has to be on or after the birth date. If it is earlier, the tool asks you to check the dates.

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