Last updated: May 2026
How old am I? Enter your birthday to get your exact age, next birthday countdown, and more.
Date of Birth
Life Milestones
Age is calculated from date of birth to the selected "as of" date using calendar months and days.
Age calculation sounds simple — subtract the birth year from the current year — but it gets complicated fast. Your age on January 1st is different from your age on December 31st. And "how many days old am I?" requires tracking leap years, month lengths, and whether the current year's birthday has passed yet.
The standard method: count complete years first (the number of times your birthday has passed), then count remaining months, then remaining days. This calculator handles all of it — including the leap year edge case where someone born on February 29th turns one year older on March 1st in non-leap years.
| Age | Legal / Social Significance | Country Notes |
|---|---|---|
| 13 | Social media accounts (COPPA) | US federal minimum |
| 16 | Driving license eligibility | US (varies by state) |
| 18 | Legal adult, voting, contracts | Most countries |
| 21 | Alcohol, cannabis (US) | US-specific |
| 25 | Full brain development (prefrontal cortex) | Neuroscience consensus |
| 59½ | Early IRA/401k withdrawal, no penalty | US retirement accounts |
| 62 | Earliest Social Security eligibility | US — reduced benefit |
| 67 | Full Social Security retirement age | US (born 1960 or later) |
What happens if you're born on February 29th (leap day)?
In non-leap years, your birthday is celebrated on either February 28th or March 1st depending on the country and legal system. The US and UK typically use February 28th as the legal birthday. For age calculation purposes, most systems count the birthday as having passed on March 1st in non-leap years.
How many days old am I?
Enter your birthdate above and the calculator will show your total days lived, including adjustments for leap years. As a rough estimate: multiply your age in years by 365, then add 1 extra day for every 4 years (leap years), plus the days since your last birthday.
Is age calculated the same way everywhere in the world?
Mostly, but not entirely. In South Korea, the traditional system adds one year at birth and then again every New Year's Day — so a baby born on December 31st is "two years old" by the following January 1st. Korea officially phased out this system in 2023, but it's still culturally used. East Asian age reckoning also counts the year of birth as year one, making ages one year higher than Western calculations.
What is my age in months or weeks?
The "Age (precise)" result above shows your exact age in years, months, and days. For months: multiply complete years by 12, then add the remaining months shown. For weeks: take your total days lived and divide by 7. A 30-year-old has lived approximately 1,565 weeks.
How does the zodiac sign calculation work?
Western zodiac signs are based on the date of birth and the sun's position on the ecliptic. Each sign spans roughly 30 days. The calculator uses exact cutoff dates: Aries (Mar 21 – Apr 19), Taurus (Apr 20 – May 20), and so on. Note that the exact boundary date can shift by a day depending on the year due to how the solar calendar works.