Tool
Age Calculator
Calculate an exact age in years, months, and days for any reference date.
Try it
This tool runs entirely in your browser. Nothing you type or paste is sent anywhere.
36 years, 4 months, and 9 days as of the reference date.
How it works
- Parsed the birth date and reference date as UTC calendar dates.
- Subtracted year, month, and day components and borrowed from the larger unit when needed.
- Also computed the totals: whole days and whole months.
- That is 13281 whole days (436 whole months).
Usage
- Enter the birth date.
- Optionally set the reference date (today by default).
- Read the exact age and the totals in days and months.
Examples
Exact age
{
"birthDate": "1990-05-15",
"reference": "2026-09-24"
}Limitations
Why 'years, months, days' is not a duration
Months and years have variable length, so an exact age must be expressed as calendar components. The totals (days and months) give a single number for comparisons, while the components give the colloquial answer.
Frequently asked questions
- Why can the age differ by a day?
- Calendar arithmetic in UTC can disagree with local time around midnight. Use a reference with an explicit time when that matters.