Age Calculator
Calculate exact age in years, months, weeks, and days from any date of birth.
Returns days until next birthday and total days lived since birth date.
The age calculator computes the exact difference between your date of birth and a target date (today by default).
How it works: The calculation subtracts the birth date from the target date, breaking the result into years, months, and days. It handles varying month lengths (28-31 days) and leap years (every 4 years, except centuries not divisible by 400) automatically.
Age = Target Date - Date of Birth
What each result means:
- Years, months, and days — your precise chronological age
- Total days alive — the raw number of days between the two dates
- Days until next birthday — a countdown to your upcoming birthday
When to use this calculator:
- Verify your exact age for official documents or applications
- Calculate someone’s age on a specific date (past or future)
- Find out how many days until a birthday or anniversary
- Determine age differences between two people (calculate each, then compare)
Practical example: If you were born on March 15, 1990 and today is March 26, 2026, you are 36 years, 0 months, and 11 days old. You have been alive for 13,160 days. Your next birthday is 354 days away.
Tips: You can set the target date to any date in the future or past. This is useful for calculating how old someone was at a historical event, or how old you will be on a future milestone date. For legal purposes, most jurisdictions consider you a year older on the anniversary of your birth date, not the day after.