Age Calculator
Calculate your exact age in years, months and days from your date of birth. See how many days old you are and how long until your next birthday.
Enter a date of birth, then press Calculate age.
By Shah Rukh, software developer · Last updated:
How this age calculator works
The calculator counts complete years first, then complete months since your last birthday, then the days left over. It uses calendar dates only, so time zones and daylight saving time never change the result.
Worked example
Someone born on August 15, 1995, on September 27, 2026:
- Their 31st birthday was August 15, 2026, so they are 31 years old.
- From August 15 to September 15 is 1 month.
- From September 15 to September 27 is 12 days.
Age: 31 years, 1 month and 12 days.
Leap years and month lengths
Months have 28, 29, 30 or 31 days, which is why “counting months” can be tricky. When your birth day doesn’t exist in a month (for example, the 31st in a 30-day month), the calculator uses the last day of that month. People born on February 29 are treated as having their birthday on February 28 in non-leap years.
Uses for an age calculator
- Checking age limits for school admission, exams, jobs, visas or sports categories on a specific cut-off date.
- Finding out how old someone was on a historical date.
- Counting down to a birthday, or celebrating a milestone like 10,000 days old.
Age in different cultures
Most countries count age from zero at birth, which is what this calculator uses. Traditional East Asian age reckoning started at one and added a year at the New Year. South Korea officially switched to the international method for legal purposes in 2023.
Frequently asked questions
How do I calculate my age from my date of birth?
Subtract your birth year from the current year, then subtract one more if your birthday hasn’t happened yet this year. For months and days, count forward whole months from your last birthday, then the remaining days.
How many days old am I?
Enter your date of birth above. The calculator shows the total number of days you have been alive, as well as weeks and months.
How is age calculated for people born on February 29?
In non-leap years this calculator treats February 28 as the birthday, which is common practice. Some countries use March 1 for legal purposes.
Can I calculate age on a past or future date?
Yes. Change the ‘Age at’ date to any date, for example to check how old someone was on a certain day or will be on a deadline.
Does this count the day of birth?
No. The result counts complete days between the two dates, which is how age is normally measured. On your birthday, you are exactly a whole number of years old.