Age Calculator
How old someone is in years, months and days, and how long until the next birthday.
Age in completed years, months and days, plus the running totals people actually enjoy — days and weeks lived — and the date of the next birthday.
How it works
Age is counted the way birthdays are: completed years first, then whole months, then the days left over. That is not the same as dividing the total days by 365, because months and years have different lengths and leap years exist.
Leave the second field empty to measure from today. Fill it in to ask how old someone was, or will be, on a particular date — and to get a link whose answer does not change tomorrow.
Examples
| Case | Input | Result |
|---|---|---|
| An age on a given day | Born 1990-06-15, measured on 2026-01-01 | 35 years, 6 months and 17 days |
| Born on a leap day, in a year without one | Born 2000-02-29, measured on 2026-02-28 | 25 years, 11 months and 30 days |
Frequently asked questions
What happens with a 29 February birthday?
In a common year there is no 29 February, so the anniversary is shown as 1 March. Some jurisdictions treat 28 February as the legal date instead; the calendar has no opinion, so a convention has to be picked and this is the one used here.
Why does the answer change if I leave the date empty?
Because it is measured from today, and today moves. Fill in the second field to pin the answer to a date, which is also what makes the link worth sharing.
Which time zone decides what "today" is?
UTC. Close to midnight your local date may differ by a day; entering the date explicitly removes the ambiguity.
Good to know
- With the second field left empty the result depends on the day it is computed, so it is not fixed the way the other calculators are.