Age Calculator

This age calculator measures the exact span between your birth date and any target date — counting full years, remaining months, and leftover days separately. It handles leap years correctly, so if you were born on February 29, your birthday is counted on March 1 in non-leap years.

Under the hood, the math is straightforward: subtract the birth year from the current year, then adjust if your birthday hasn't occurred yet this year. The "days" component is the trickiest part — month lengths vary from 28 to 31 days, so the calculator accounts for each month individually. For month boundaries, the rule is: Feb. 20 to Mar. 20 = exactly one month, regardless of how many days February has. This is the standard convention for handling the uneven number of days across different months.

Note that this is chronological age — the Western standard. In East Asian age reckoning — still common in Korea, China, and Japan — you're considered 1 year old the moment you're born, and you gain a year every Lunar New Year rather than on your actual birthday. A child born one day before the Lunar New Year celebration would be considered 2 years old just two days later. Our calculator uses the international standard (Western) system. Our age calculator uses this convention by default.