Time/Numbers
Age Calculator
Exact age from a birth date — years/months/days, total time lived, and the next birthday.
This tool calculates exact age from a birth date: full years, months, and days lived, the total number of days lived, and how much time is left until the next birthday.
How to use it
- Enter a birth date and the age is calculated instantly as of right now.
- Change the "calculate age as of" date to anything else, including a future date, if needed.
- The total number of days lived is shown separately — handy for spotting a milestone like day 10,000.
Common uses
- Checking an exact age for a form that requires confirming adulthood or a minimum age.
- Counting down the days until a birthday to plan a gift or celebration.
- Calculating age as of a specific future date — for example, how old a child will be at graduation.
Things to keep in mind
For people born on February 29, a "full year" in a non-leap year is conventionally counted as reached on March 1 — a rule that varies between jurisdictions.
The calculation accounts for timezone — an age "as of this second" can differ by a day depending on the chosen timezone if the birth moment is close to midnight.
Article about this tool: Age calculation: why it's not just subtracting years
Frequently asked questions
How is a February 29 birthday handled?
In non-leap years, that birthday is treated as March 1 for calculating the next birthday, while the exact age in years/months/days is computed from the actual calendar difference.
At what exact moment does age increase by a year?
Precisely on the calendar birthdate — up to and including that day the age is still the previous one, and from the next day it counts as new. This matches the everyday understanding of age.
What does the "Total lived" block show?
The same span of time expressed in complete weeks and days, plus the number of complete months — handy when you need a running total rather than a years/months/days breakdown.
Why does legal adulthood begin at midnight before the birthday in some jurisdictions?
Under the "no fractions of a day" legal principle used in some jurisdictions (including the UK), a birthday counts as a fully lived day, so a given age is deemed reached from the first moment of the day before the anniversary. This is a legal technicality that doesn't match everyday age counting.
Can I calculate age as of a future date rather than today?
Yes, the "Calculate age as of" field accepts any date, including a future one — handy for finding out how old someone will be on a specific upcoming event.