Age Calculator
Exact age in years, months and days from a birth date.
Quick answer
- Formula: Age = calendar breakdown of (age-at date − birth date); totals counted in whole months and days (UTC)
- Worked example — Age (full years): 34 (full example below).
Age Calculator
| Age (full years) | 34 |
| Total months | 413 |
| Total days | 12,582 |
| Total weeks (full) | 1,797 |
| Age breakdown | 34 years, 5 months, 12 days |
Born January 15, 1990, a person is 34 years, 5 months and 12 days old on June 27, 2024 — 12,582 days in total.
Enter a date of birth and the date you want the age at, and this calculator works out the exact age: full years, months and days, plus the total months, days and weeks lived.
It handles leap years and different month lengths properly, so a birthday that falls after February 29 is counted exactly the way a calendar counts it.
The formula
Worked example
Born January 15, 1990, a person is 34 years, 5 months and 12 days old on June 27, 2024 — 12,582 days in total.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
How is age calculated exactly?
Full years are counted first from the birth date, then full calendar months from the last birthday, then the remaining days. Month lengths and leap years are taken from the real calendar.
What if someone was born on February 29?
In a non-leap year their birthday is treated as reached on February 28 for the full-years count by this calculator's month-addition rule, which matches the common legal convention in many places.
Why enter an 'age at' date instead of using today?
So the result is exact for any reference date — a school cutoff, an application deadline, or a future birthday — and never depends on when you happen to run it.
Category: Date & Time calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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