How to use this calculator
- Enter or choose date of birth.
- Enter or choose age on.
- The years updates as you type. Use Copy result or Share to keep it.
Method
Count the whole months from the birth date that fit before the target date (a month ending on a shorter month is clamped to its last day), split them into years and months, then count the remaining days.
Worked example
- From 20 May 1990, 33 years reach 20 May 2023.
- 9 more months reach 20 February 2024.
- From 20 February to 15 March 2024 is 24 days (2024 is a leap year, so February has 29 days).
On 15 March 2024 someone born on 20 May 1990 is 33 years, 9 months and 24 days old.
What the result means
Someone born on 29 February has their birthday counted on 28 February in common years. Some legal systems use 1 March instead; check the rule that applies to you.
Assumptions and limits
- Gregorian calendar dates, without time of birth or time zones.
- Ages in other calendar systems (for example East Asian age reckoning) are not calculated.
Questions
How many days old am I?
The “total days” result gives the exact number of days between the two dates.