Age Calculator by Date of Birth
Find your exact age by entering your date of birth. Our free online tool calculates age in years, months, days, hours, minutes, and seconds — updated as you type.
Calculate Age from Date of Birth
An age calculator by date of birth is one of the most commonly used online tools. Simply enter your date of birth (DOB), and the calculator does the rest — accounting for leap years, different month lengths, and daylight saving time where applicable.
Knowing your exact age can be useful for medical purposes, filling out forms, retirement planning, or just for fun. Our calculator also shows milestone information like total days lived, hours lived, and your next birthday countdown.
All calculations happen entirely in your browser. Your date of birth is never stored, transmitted, or shared with any third party. Use it as many times as you like, completely free.
Frequently Asked Questions
How does an age by date of birth calculator work?
The calculator takes your date of birth and compares it to the current date. It subtracts the birth year, checks whether your birthday has passed this year, and calculates the exact difference in years, months, days, and smaller time units. All leap years and month-length variations are handled automatically.
How many days have I been alive?
Our calculator shows the total number of days you have lived since birth, including all leap days. This number updates in real-time as you type your date of birth, giving you an immediate answer without any button clicking.
Can I calculate age for someone born on February 29?
Yes. For leap day babies, our calculator uses the standard convention: in non-leap years, March 1 is treated as the birthday equivalent. The calculator handles this edge case correctly and shows accurate age in all time units.
Do I need to click a button to calculate my age?
No. Our age calculator updates results instantly as you type — there is no calculate button to press. This makes it one of the fastest and most convenient DOB calculators available online.
Can I use this tool on my phone?
Yes, the calculator is fully responsive and works on any device. The date input fields are optimized for touch with large tap targets and numeric keyboard on mobile phones.