Calculate exact age online
This age calculator works out the precise time between a date of birth and any other date. It shows the answer in years, months and days, together with the total number of months, weeks and days, the weekday you were born on and a countdown to your next birthday.
How to use the age calculator
- Select the date of birth.
- The Age on date is set to today. Change it to calculate age on any past or future date.
- Results update instantly.
How age is calculated
The calculator counts full years first, then full months, then the remaining days, taking the different lengths of months and leap years into account. For example, someone born on 15 May 1990 is 36 years, 4 months and 10 days old on 25 September 2026.
Useful for
- Application forms that ask for age on a specific date, such as school admission, jobs, exams and visas
- Checking eligibility for age limits
- Planning birthdays and anniversaries
- Working out the age of a business, property or document
Need other quick maths? Try the percentage calculator.
Example calculation
Someone born on 15 May 1990, on 28 September 2026, is:
- 36 years, 4 months and 13 days old
- 436 months in total
- about 1,897 weeks, or 13,285 days
Age in different systems
Most countries count age in completed years since birth, which is what this calculator uses. Some cultures traditionally used other systems. For example, the traditional Korean system counted a baby as one year old at birth, although South Korea officially adopted the international system in 2023.
Common uses
- Applications and forms that ask for age “as on” a cut-off date, such as exams, jobs, school admissions and sports categories.
- Checking eligibility for age limits, pensions or insurance.
- Planning birthdays and milestones like your 10,000th day.
- Genealogy: working out ages at historical dates.
Leap years
A leap year has 366 days, with 29 February. Years divisible by 4 are leap years, except century years not divisible by 400 (so 2000 was a leap year, but 1900 was not). The calculator accounts for leap years and the different lengths of each month automatically.
Need percentages instead? Use the percentage calculator.
Frequently asked questions
Can I calculate age on a future date?
Yes. Change the "Age on" date to any date, past or future.
Does the calculator handle leap years?
Yes. Leap years and the different lengths of each month are included in the calculation.
How is age counted for someone born on 29 February?
In non-leap years the calculator counts the birthday as 1 March, which is the usual convention.
Is my date of birth stored?
No. The calculation happens in your browser and nothing is saved.