Age Calculator
Calculate exact age in years, months, and days from a birth date, plus total days lived and a countdown to the next birthday.
Recommended Settings
Pro Tips
- •Age is calculated by default as of today, but you can set any other reference date to check someone's age at a specific point in time
- •The years/months/days breakdown accounts for varying month lengths, so it's more precise than simply dividing total days
- •Total days lived is a fun fact that also doubles as a useful figure for some eligibility calculations
- •Days to next birthday counts forward from your chosen reference date, not necessarily from today
Most Popular
Most users calculate age as of today's date to check their own or someone else's current exact age
When to Use This Tool
Get a precise age in years, months, and days for an official form or application.
See exactly how many days remain until the next birthday.
Confirm someone's exact age as of a specific date for an eligibility requirement.
Check how many total days someone has been alive as a fun milestone.
How It Works
Calculate the difference between the birth date and the reference date in years, months, and days, adjusting for varying month lengths
Calculate the total number of whole days between the two dates
Find the next occurrence of the birth month and day after the reference date to count down to it
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side calendar date arithmetic for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Can I calculate someone's age at a past or future date?
Yes, change the 'Calculate age as of' field to any date to see what someone's age was or will be at that point in time.
How is the years/months/days breakdown calculated?
It accounts for the actual number of days in each month, so the result is precise rather than using a simplified average month length.
Is my data sent to a server?
No. The calculation happens entirely in your browser.
What happens if I enter a birth date in the future?
The calculator requires the birth date to be on or before the reference date, since a negative age isn't meaningful.
Does this account for leap years?
Yes, the underlying date arithmetic uses standard calendar calculations that correctly account for leap years.