Calculate exact age from a birth date in years, months, and days. Includes total days, hours, next birthday countdown, zodiac sign, Chinese zodiac, birthstone, and more.
Your Age
Fun Facts
Age Calculator is a free online tool that computes your exact age from a birth date to any reference date. It provides a precise calendar-accurate breakdown in years, months, and days, plus absolute totals in days, weeks, hours, minutes, and seconds. The tool also shows your next birthday countdown, zodiac sign, Chinese zodiac, birthstone, day of birth, and other fun facts — all calculated instantly in your browser with no data transmitted to any server.
Use Age Calculator whenever you need to determine an exact age for legal documents, insurance applications, eligibility verification (voting age, retirement), employment forms, school enrollment age requirements, or simply out of curiosity. It is also useful for calculating how old someone was on a specific historical date by changing the reference date.
HR professionals use Age Calculator for verifying employee ages and calculating retirement eligibility dates. Parents use it to check school enrollment eligibility based on age cutoff dates. Healthcare providers use it for pediatric age calculations where precision matters. Developers use it to verify date arithmetic in applications. It is also commonly used for personal milestones: calculating exact age for celebrations, checking zodiac compatibility, or counting down to the next birthday.
Essential terms and definitions related to Age Calculator.
The exact amount of time that has passed since a person's date of birth, measured in years, months, and days. This is the standard way age is calculated for legal, medical, and administrative purposes. It differs from biological age (estimated physical condition) or psychological age (cognitive and emotional maturity).
In Western astrology, one of twelve 30-degree sectors of the ecliptic, each associated with a constellation. The zodiac sign is determined by the position of the Sun at the time of birth. The twelve signs are: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces.
A 12-year cycle of animal signs used in Chinese astrology and culture. Each year is associated with one of twelve animals: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, and Pig. The animal is determined by the birth year. Each animal is believed to influence personality traits and fortune.
A calendar year that contains an extra day (February 29) to account for the fact that the Earth's orbit around the Sun takes approximately 365.2422 days. A year is a leap year if it is divisible by 4, except for years divisible by 100, unless also divisible by 400. Thus 2000 and 2024 are leap years, but 1900 and 2100 are not.
The Age Calculator uses calendar-accurate arithmetic that correctly handles leap years, varying month lengths (28–31 days), and timezone-independent date comparison. The result matches how age is legally and conventionally determined: by counting complete calendar years, then remaining months, then remaining days.
Yes. The "Age As Of" field lets you enter any reference date. By default it uses today, but you can change it to calculate how old someone was on a specific date (e.g., a historical event) or will be on a future date (e.g., a retirement or milestone date).
The Western zodiac sign is determined by the birth month and day based on the standard tropical zodiac date ranges used in Western astrology. The Chinese zodiac is determined by the birth year using the traditional 12-year cycle (Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig).
The birthstone displayed follows the modern birthstone list standardized by the American Gem Trade Association: January (Garnet), February (Amethyst), March (Aquamarine), April (Diamond), May (Emerald), June (Pearl), July (Ruby), August (Peridot), September (Sapphire), October (Opal), November (Topaz), December (Tanzanite).
Yes. If someone is born on February 29 (leap day), the calculator correctly computes their age. For non-leap years, the tool treats March 1 as the next birthday equivalent. The "Leap Year Born" indicator in the fun facts section shows whether the birth year was a leap year.
Common errors developers encounter and how to resolve them.
Age shows 0 years 0 months 0 days This means the birth date and reference date are the same day. Change the reference date to a later date, or verify you entered the correct birth date.
Birth date cannot be in the future error The birth date you entered is after the reference date. Either change the birth date to an earlier date, or change the "Age As Of" date to a date after the birth date.