Age Calculator
Enter a date of birth and get an exact age in years, months and days, plus the total days lived and a countdown to the next birthday.
- Category
- Calculators
- Updated
- Cost
- Free · no sign-up
Age
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Enter a date of birth to see the exact age.
What this calculator does
An age calculator converts two dates into a duration expressed the way people actually talk about age: completed years, then the leftover months and days. That sounds trivial, but doing it by hand is where mistakes creep in — months have different lengths, leap years shift the count, and "how old will they be in September" depends on the exact birthday.
The calculation here counts completed periods. Someone born on 3 May 1990, measured on 2 May 2026, is 35 — not 36 — because the birthday hasn't arrived yet. That matches how age is used for school years, insurance bands, legal thresholds and medical dosing.
Why the "as of" date matters
Most of the time you want today's date, which is the default. The second field becomes useful when you're checking a rule rather than a person:
- School cut-offs — will a child be five by 1 September?
- Eligibility windows — will someone be 18 on the date of an event?
- Historical ages — how old was someone when a photograph was taken?
Set the second date to the cut-off and read the result directly.
Reading the totals
Underneath the headline you get the same span expressed in months, weeks, days and hours. These are running totals, not remainders — the "total days" figure is every day lived, not the days since the last birthday.
A note on leap years
A person born on 29 February has a birthday that only exists every four years. This calculator treats 1 March as the anniversary in common years, which is the most widely used convention and matches how most legal systems handle it.
How to use the Age Calculator
Three steps, no sign-up.
Enter the date of birth
Type or pick the birth date. The calculator accepts any date from 1900 onwards.
Choose the date to measure to
It defaults to today, but you can set any future or past date — useful for eligibility cut-offs.
Read the breakdown
The headline shows completed years, months and days. Below it you get totals in months, weeks and days.
Worked examples
Someone born on 14 March 1992, measured on 1 August 2026
- Inputs
- Born 1992-03-14 · As of 2026-08-01
- Result
- 34 years, 4 months, 18 days