Dates
Defaults to today. Change it to see age on another day.
Age
About this age calculator
This tool counts exact chronological age from a date of birth: years, months and remaining days. Set “age on date” to see how old someone was — or will be — on a contract, school year, visa or birthday.
It uses the civil calendar, not a 365.25-day average, so February 29 is handled as a real calendar day. All math runs in your browser; dates are not sent to a server.
How age is counted
Years are full birthday anniversaries. Months are complete months after the last anniversary. Days are what remains after those months. If the day-of-month has not occurred yet in the current month, the previous month’s length is used (28–31 days).
How to calculate age from a date of birth
- Enter the date of birth: Use the calendar field. Invalid dates (31 February) are rejected.
- Choose the as-of date: Leave it on today, or pick a past or future date.
- Read years, months and days: The result updates as you type, with total days and the wait until the next birthday.
Frequently asked questions
How do you calculate age in years, months and days?
Count whole years to the last birthday, then whole months, then leftover days. That is the same method used on official forms, not a conversion of total days into 365.25-day “years”.
What if someone was born on 29 February?
In a leap year the birthday is 29 February. In other years this calculator treats the next birthday as 28 February, which is the usual civil convention.
Can I calculate age on a past or future date?
Yes. Change “age on date”. Useful for age on a school cutoff, a visa, or “how old will I be on this day”.
Are my dates uploaded?
No. The calculation is JavaScript in your browser. Nothing is stored on QwHub servers.