Age Calculator
Calculate exact age in years, months, and days between any two dates.
Qu’est-ce que Age Calculator ?
An age calculator computes the exact span between two dates — typically a birth date and today — expressed as calendar years, months, and days rather than a raw day count. This matters because "age" as people actually use it follows the calendar (someone born on March 15 turns a year older every March 15, regardless of how many days that particular year happened to contain), so a naive division of total days by 365.25 produces a number that's close but not exactly what a birth certificate, legal document, or everyday conversation means by "age." This tool also reports the total number of days lived and a countdown to the next birthday as secondary figures, and supports calculating age as of any date, not just today — useful for eligibility rules, historical calculations, or legal age-at-a-specific-date questions.
Comment utiliser Age Calculator
- Enter a birth date.
- The "as of" date defaults to today — change it to calculate age as of any other date (e.g. a contract's effective date, or an eligibility cutoff).
- Your exact age appears as a years/months/days breakdown, plus the total number of days lived and a countdown to the next birthday.
Exemples
Age today
Entrée : Birth date: 2000-01-15, As of: today
Sortie : Exact years, months, and days old, plus total days lived
Age as of a specific date
Entrée : Birth date: 1995-06-10, As of: 2025-01-01
Sortie : Age as of that cutoff date — useful for eligibility rules with a fixed reference date
Erreurs courantes
- Expecting "total days" to equal years × 365 exactly — leap years mean it won't, by a few days per typical lifespan.
- Assuming a February 29th birthday always rolls to February 28th — as noted above, this tool (and not every system) rolls it to March 1st in non-leap years.
- Setting the "as of" date before the birth date — the tool will flag this as an error rather than showing a nonsensical negative age.
Pourquoi utiliser cet outil
- Calculates real calendar age (years/months/days), not just a rough day-count division.
- Works for any "as of" date, not only today — useful for eligibility rules, historical calculations, or legal age-at-date questions.
- Shows total days lived and a countdown to the next birthday as a bonus, not just the headline age.
- Runs entirely client-side — no date of birth is ever sent anywhere.