Age Calculator

The Age Calculator tool works out your exact age in years, months, and days from your date of birth. Calculation runs in your browser, so your data stays private.

Use it to confirm eligibility, fill in forms, or simply see how many days you have lived — all from a single date entry.

Age calculation is needed more often than it might seem. Filling in forms that require your exact age, confirming eligibility for a service or competition, calculating the age difference between two people, or simply satisfying curiosity about how many days you have lived — all call for a precise count rather than an estimate. The tool gives an exact breakdown in years, months, and days from a single date entry.

You can calculate age as of today or as of any target date you choose, which is useful for working out age on a future event date or a past milestone. The result counts full years first, then remaining months, then remaining days, so the breakdown is precise down to the day and correctly handles leap years and varying month lengths.

Age calculation runs entirely in your browser using native JavaScript date arithmetic. When you enter a date of birth and optional target date, the tool computes the difference between the two dates by counting full years, then the remaining full months, then the remaining days, correctly accounting for leap years and the varying number of days in each month.

Your date of birth never leaves your device — there is no upload, no server-side processing, and no copy retained after you close the tab. The calculation is instant because it operates on the date values in memory. The target date defaults to today if you leave it blank, so you can calculate current age or age on any specific date.

The tool counts complete units, so someone born on 15 March shows one year older on 15 March of the next year, not on 1 January. For related calculations, use the Percentage Calculator for growth rates and the BMI Calculator for health screening.