Everyday
Age Calculator
Enter your date of birth to get your exact age in years, months, and days, with total days lived, a countdown to your next birthday, and the weekday you were born on.
How it works
Behind the numbers
The calculation starts with your birth date and a reference date, today unless you pick another. It counts complete years first. When your birthday has not arrived yet in the reference year, it borrows a year and counts the shortfall in months, then does the same for days using the length of the previous month. This is the same borrow method you would use on paper, so uneven month lengths are handled exactly.
Leap years need no approximation either. February 29 only counts toward the totals when it actually happened. If you were born on February 29, the next-birthday countdown treats February 28 as your birthday in non-leap years, which is the most common convention. The totals in days, weeks, and months come from the raw day difference, independent of the year, month, and day breakdown.
You can change the reference date to any day, past or future. Leave it on today for your current age, or move it to answer questions like how old you will be on a trip, or how old you were on a past date. Everything runs in your browser. Your birth date never leaves the page.
FAQ
Questions, answered
How do I calculate my exact age?
Subtract your birth date from the reference date the way you subtract on paper: count full years first, then full months, then the remaining days. When the birthday or the day-of-month has not arrived yet, borrow from the next larger unit. Leap years and uneven months fall out of the arithmetic instead of needing special rules. The calculator above runs the same steps.
Can I calculate my age on a specific date?
Yes. Change the reference date to any day in the past or future and every result updates at once. People use this for forms that ask for age on a cutoff date, eligibility checks, or to see how old they will be on an upcoming date.
How do leap years affect the result?
February 29 counts toward your total days only in years when it existed. If you were born on February 29, the next-birthday countdown uses February 28 in non-leap years, which matches the most common convention.
Why does my age differ from another calculator's?
Three conventions vary between calculators: whether the start day counts inclusively, how February 29 birthdays are treated in non-leap years, and whether the math uses your local timezone or UTC. This page counts exclusive of the start day and works in local dates.
Is this calculator free?
Yes. No sign-up, no cost, and it works on any device. The math runs entirely in your browser, so your birth date is never sent anywhere.