Age Calculator
Age Calculator works out an exact age from a date of birth — in years, months and days — and also shows the total in months, weeks, days and hours. By default it measures to today, but you can set any target date.
It uses calendar-aware math, so month lengths and leap years are handled correctly.
How to use Age Calculator
- 1
Enter the date of birth
Pick the birth date with the date field.
- 2
Optionally set a target date
Leave the second field blank to measure to today, or choose any date.
- 3
Read the age
The exact age and several totals appear instantly.
How exact age is calculated
Age in years, months and days is calculated by comparing the calendar components of the two dates and borrowing from the previous month when the day-of-month is negative — the same way you would count it by hand.
Because real months have different lengths and leap years add a day, a simple 'days ÷ 365' estimate drifts over time. Calendar-aware counting avoids that drift.
Common uses
Use it to find an exact age for forms and eligibility checks, to count down to a milestone birthday, or to express an age in days or weeks for a baby.
Setting a custom target date also lets you answer 'how old will I be on this date?' or 'how old was someone on a past event?'.
Frequently asked questions
- Does it account for leap years?
- Yes. The calculation uses real calendar dates, so leap years and varying month lengths are handled correctly.
- Can I calculate age at a past or future date?
- Yes. Set the second date field to any date to measure the age at that point instead of today.
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