Age Calculator
Calculate your exact age in years, months and days from any date of birth.
All calculations happen locally in your browser — nothing is uploaded, stored or tracked.
Enter your date of birth
Use the date picker or type it in the YYYY-MM-DD format.
Pick a calculation date
Defaults to today — change it to check an age on any date.
Read your exact age
Years, months and days, total days lived and your next birthday.
What Is an Age Calculator?
An age calculator works out a person's exact age from their date of birth and a chosen reference date — usually today. Instead of a flat number of years, it reports the age as full years, remaining months and remaining days, which is how ages are quoted in everyday life.
Getting this right means handling calendar details correctly: months have different lengths, and leap years add a 29th of February every four years (with century exceptions). The calculator also counts the total number of days lived and tells you when your next birthday falls and how long you have to wait for it.
How the Calculation Works
The age is computed by walking backwards from the reference date: first count complete years until the last birthday, then complete months from that birthday, then the remaining days. Leap-day birthdays (29 February) are handled by treating the anniversary as 28 February in non-leap years.
Example Calculation
If you were born on 15 March 2000 and the reference date is 14 August 2026, you have completed 26 years (your birthday on 15 March 2026 passed), then 4 full months (March 15 → July 15) and 30 days (July 15 → August 14): 26 years, 4 months, 30 days.
Your data never leaves your device.
Every calculation on this site runs in your browser using vanilla JavaScript. Nothing is uploaded, stored or tracked.
- 100% local, client-side calculations
- No data stored on any server
- No tracking, no analytics, no ads scripts
- Works offline once loaded
Frequently Asked Questions
How do I calculate my age by date of birth?
Subtract your birth year from the current year, then adjust for whether your birthday has already occurred this year. The exact result in months and days is what this calculator shows.
How old am I in days?
The calculator counts the exact number of days between your date of birth and the reference date, including leap days.
How is a leap-year birthday (29 February) handled?
In non-leap years the birthday is treated as 28 February, which is the convention most official systems use.
Can I calculate someone else's age?
Yes — enter any date of birth and any reference date; the calculator works for any two dates.
Why does the calculator show years, months and days separately?
Because "26 years old" hides how many months and days have passed since the last birthday. The three-part breakdown is exact.