Age Calculator
Calculate exact age in years, months, days, hours, and minutes.
Pick a date of birth and (optionally) an as-of date. Returns exact age plus the date of the next birthday.
How age is calculated
This calculator gives you exact age in multiple units: years/months/days (the way you would say it out loud), plus total months, weeks, days, hours, and minutes. It correctly handles leap years and varying month lengths.
What "exact age" means
Age in years counts only completed years. Someone born March 15 who is "20 years old" on March 10 of their 20th-21st year has been alive for nearly 21 years but is still 20 until the 15th. This is the standard convention used in legal documents, medical records, and forms.
Common uses
- Health forms: exact age in years, months, days for pediatric records
- Legal: verifying eligibility (voting, drinking, retirement, Social Security claiming)
- Curiosity: how many days you have been alive, total hours lived
- Pet ages: works equally well for figuring out a dog's or cat's exact age
- Project age: "how long has this been running" for products, businesses, anniversaries
As-of-date
Leave the "as of" field blank to calculate age today. Set it to a future or past date to find what someone's age was or will be on that day. Useful for "how old will I be on X date" planning.