Age Calculator
Exact age in years, months, days and totals.
Leave the second date blank to calculate the age as of today.
How to use
- 1 Enter the date of birth.
- 2 Optionally enter a second date to measure the age at that point.
- 3 Leave the second date blank to use today.
- 4 Read the years, months and days, plus total days and weeks.
About Age Calculator
The Age Calculator works out exactly how old someone is from a date of birth, broken down into whole years, months and days rather than a single rounded number.
Enter a birth date and it tells you the age as of today, or supply a second date to find the age on any past or future day — handy for working out how old you will be at a wedding, or how old a relative was on a particular anniversary.
Alongside the calendar breakdown it gives running totals: the total number of days lived and the total number of weeks, which are surprisingly satisfying figures and useful for milestones like a baby reaching 100 days or 1000 days old.
The hard part of age maths is handling months of different lengths and leap years; a naive subtraction trips over February and the end of long months.
This tool counts whole months from the birth date and clamps short months correctly, so a date such as the 31st never produces an impossible or negative result.
Everything is computed in your browser from the two dates you provide, so nothing about your birthday is ever uploaded or stored, and it keeps working offline.
Pass an explicit "age at" date for a fully deterministic answer, or leave it blank to measure against the current day.
FAQ
How are months counted across different lengths?
It counts whole months from the birth date and clamps to the end of short months, so the 31st of a month is handled correctly and the days figure is never negative.
Can I find my age on a future date?
Yes. Enter any later date in the second field and the tool shows the age you will be on that day.
Is my date of birth sent anywhere?
No. The calculation runs entirely in your browser and nothing is uploaded or stored.