Age Calculator
Enter a date of birth to see the exact age in years, months, and days — plus total days lived, weeks, and a countdown to the next birthday.
Select a date of birth to see your exact age breakdown.
How age is measured
Age is usually expressed as a count of complete calendar years since birth — the number ticks up on your birthday each year, not after a fixed 365 days. This matters because calendar years include leap years, and calendar months have different lengths, so “6 months” from January 31 lands on July 31, not exactly 183 days later.
The precise breakdown — years, months, and leftover days — mirrors how a doctor or official form would state an age: 42 years, 3 months, and 15 days. The total days figure is the raw day count and is useful for calculations where you need an absolute number (for example, checking if someone has lived more than 10,000 days).
Frequently asked questions
How is the exact age calculated?
The calculator counts complete calendar years, then complete calendar months in the remaining period, then the leftover days — the same way you would count on a calendar. For example, if you were born on March 15 and today is June 10, the result is 2 months and 26 days (not a fixed 30 days per month).
Why does my age in months not match years × 12?
The months figure shown in the breakdown is the remainder after whole years are subtracted. Total months is shown separately in the stat cards and does equal years × 12 + remainder months.
How are total days calculated?
Total days is the simple calendar difference between your birth date and today — no time zones, no clock offsets. It counts the number of midnight-to-midnight periods elapsed, so leap days are included automatically.
What does the progress bar show?
The bar shows how far through your current year of life you are — measured from your last birthday to your next birthday. At your birthday it resets to 0%; the day before it reaches ~100%.
When is my next birthday?
The calculator finds the next calendar date that matches your birth month and day. If today is your birthday, it shows 0 days. For February 29 birthdays, most systems (and this tool) use March 1 in non-leap years.
Is my date of birth sent to a server?
No. All calculations run entirely in your browser. Nothing is transmitted or stored.