Age Calculator is a free browser-based utility for calculating age from a date of birth. It is designed to make a common date calculation clear and fast on phones, tablets and desktop computers.
The main tool reports age in calendar years, months and days. It also provides optional details such as the weekday of birth, days until the next birthday, total calendar months, and elapsed weeks, days, hours, minutes and seconds.
Age is easy to estimate but surprisingly easy to calculate incorrectly around month boundaries and leap years. A simple “current year minus birth year” calculation can be wrong if the birthday has not yet occurred. Dividing elapsed days by 365 also ignores leap years and variable month lengths.
This site therefore uses calendar-based date arithmetic for the primary age result and clearly separates that result from duration totals such as weeks or hours.
The calculator counts completed calendar years first, completed months second, and remaining days last. The detailed totals are computed from the actual difference between the selected dates. February 29 birthdays use February 28 as the anniversary in non-leap years within this tool.
All age calculations are performed in JavaScript in the visitor's browser. The site does not require an account or a server-side date-of-birth database.
Explanatory content on this site is written to help users understand what the calculator is doing, where a result is useful, and where an official source is still required. We avoid presenting the calculator as legal, medical, financial or identity-verification advice.
If calculation behavior changes, the supporting explanations should be updated with it so the page describes the tool users are actually using.
For any decision that has legal or administrative consequences, use the date of birth shown on the relevant accepted record and follow the cut-off-date rule set by the responsible authority. A browser calculator can assist with arithmetic but cannot validate identity or determine which legal rule applies.