Age Calculator
Find out exactly how old someone is in years, months, and days — updated to any reference date you choose.
How it works
- 1
Enter a date of birth in YYYY-MM-DD format — the age appears immediately.
- 2
Leave "Age on" blank to calculate against today, or set a past or future date to see the age at that moment.
- 3
The result shows years, months, and days alongside the total day count. Nothing you enter is sent anywhere.
Questions
How is the age calculated?
The calculation counts whole calendar months from the date of birth, then counts leftover days from that anchor. It never divides total days by 365.25 — that approach drifts around leap years.
What happens when someone is born on 29 February?
In a year without a 29 February, the birthday is counted from 28 February. That is the convention most legal systems and calendar software use.
Can I calculate a future age?
Yes — enter a future date in the "Age on" field and the tool shows what the age will be on that day.
Is this calculation done on my device?
Yes. The maths runs entirely in your browser. No data is recorded or transmitted.
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