Age Calculator
Find your exact age in years, months and days on any date, with totals in weeks, days and hours, the weekday you were born, and a countdown to your next birthday.
- Exact years, months & days
- Next birthday countdown
- Leap-year aware
Dates
Enter your birth date
Your age
Pick your date of birth to see your exact age, totals and a countdown to your next birthday.
How it works
How to Use the Age Calculator
- 1
Enter the date of birth
Pick the birth date from the date field.
- 2
Choose the "as of" date
It defaults to today. Change it to see an age on any other date.
- 3
Read the results
See the exact age, the totals, the weekday of birth and how long until the next birthday.
How Age Is Calculated
Months have 28 to 31 days, so an age cannot be found by dividing days by 30 or 365. The calculator instead finds the most recent "month-anniversary" of your birth date that is not after the "as of" date. The number of whole months up to that point gives the years and months, and the days left over give the days.
- Leap years: a year is a leap year if it is divisible by 4, except century years, which must be divisible by 400 (2000 was a leap year, 1900 was not).
- Short months: a birth day of 29–31 is moved to the last day of shorter months.
- Totals: total days are the exact number of calendar days between the two dates; weeks are those days ÷ 7 with the remainder shown separately.
Examples
| Born | As of | Age |
|---|---|---|
| May 15, 1990 | Oct 22, 2026 | 36 years, 5 months, 7 days |
| Jan 31, 2023 | Mar 1, 2023 | 0 years, 1 month, 1 day |
| Feb 29, 2000 | Feb 28, 2001 | 1 year (Feb 28 rule) or 11 months, 30 days (Mar 1 rule) |
| Jan 1, 2000 | Jan 1, 2001 | 1 year (366 days, a leap year) |
Common Use Cases
Forms and applications
Check an exact age for school admissions, sports categories or job applications.
Eligibility on a date
Set the "as of" date to a deadline to see the age someone will be on that day.
Birthday planning
Count down the days to the next birthday and see which weekday it falls on.
Milestones
Find out how many days or weeks old you are, for a 10,000-days celebration for example.
Frequently Asked Questions
How does the age calculator work out years, months and days?
It counts the number of whole calendar months from your date of birth to the "as of" date, splits them into years and months, then counts the remaining days. Real month lengths and leap years are used, so the result matches the calendar rather than an average month length.
How are birthdays on the 29th, 30th or 31st handled?
When a month is shorter than your birth day, the anniversary falls on that month's last day. For example, someone born on January 31 completes one month on February 28 (or February 29 in a leap year).
I was born on February 29. When is my birthday in non-leap years?
Conventions differ, so the calculator lets you choose. By default it counts the birthday on February 28 in non-leap years; you can switch to March 1. The choice changes your exact age around that date and the next-birthday countdown.
Can I calculate age on a past or future date?
Yes. Change the "as of" date to any date on or after the date of birth, for example to check someone's age on a deadline or event day. If the "as of" date is before the date of birth, the calculator shows an error.
How are total hours calculated?
Total hours are total days × 24, counted from midnight to midnight. The calculator does not ask for a birth time or time zone, so it does not account for the hour you were born or daylight-saving changes.
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