Work out an exact age from any date of birth. Enter the birth date below to see the age in years, months and days, the total days and weeks lived, and the number of days until the next birthday.
Leave blank to use today.
Enter a date of birth to see the age.
Age is calculated in whole calendar years, months and days. Leave the second date blank to use today.
About this calculator
This calculator measures the time between a date of birth and another date, which is today unless you set a different one. It counts the number of full years first, then the full months after that, then the days left over. That is the order people use in ordinary speech when they say someone is, for example, thirty-four years and two months old. The tool also reports the total days and whole weeks lived, the day of the week the person was born on, and the western zodiac sign for the birth date.
A birthday on 29 February needs one rule. In a year that is not a leap year there is no 29 February, so for the next-birthday countdown this calculator treats the birthday as 28 February. The age in completed years still increases correctly. Leap years themselves are handled in full: 2000 and 2024 are leap years and 1900 and 2100 are not, because a century year counts as a leap year only when it divides evenly by 400.
Frequently asked questions
How is age calculated in years, months and days?
The calculator counts complete units in order. It first finds how many full years have passed since the birth date, then how many full months have passed since that anniversary, then the days left over. This matches how age is normally stated in conversation. The method allows for months of different lengths, so a birth date late in a long month is measured against the real length of each later month rather than a flat 30 days.
What is my age if I was born on 29 February?
You gain a year of age every year, the same as anyone else. The only question is which day counts as the birthday in the three years between leap years, when 29 February does not exist. Practice varies by country and by law. This calculator uses 28 February as the observed birthday in non-leap years for its next-birthday countdown, which is the more common choice for everyday celebrations. Age in completed years is not affected.
How many days old am I?
The calculator shows the total number of days between the date of birth and today, along with the number of whole weeks. This is a straight count of calendar days and includes every leap day that has fallen within the lifetime. It is a different figure from age in years, months and days, which groups the same span into larger units.
How is the countdown to the next birthday worked out?
The calculator finds the next time the birth month and day occur on or after today. If today is the birthday, the countdown shows zero. Otherwise it counts the whole days from today to that date. For a 29 February birthday in a non-leap year, the countdown points at 28 February.
What is a star sign and how is it found?
The star sign, or western zodiac sign, is one of twelve signs linked to the position of the sun at the time of birth. Each sign covers a fixed range of dates, so Aries runs from 21 March to 19 April. The calculator reads the birth date and returns the matching sign. Sign boundaries can move by a day from year to year in stricter astrology; this tool uses the common fixed dates.