Age Calculator
Find your exact age in years, months, and days — or the difference between any two dates.
Date of Birth
How to Use the Age Calculator
- Select the My Age tab to calculate your current age from your date of birth.
- Enter your birth date using the date picker. The calculator uses today's date automatically.
- Your age in years, months, and days appears immediately, along with total days lived, total weeks, the day of the week you were born, and a countdown to your next birthday.
- Switch to the Between Dates tab to find the exact time elapsed between any two calendar dates — useful for calculating work anniversaries, contract durations, or event countdowns.
How Age Is Calculated
Age calculation sounds simple but has a few subtleties. A person born on March 15, 2000 turns 25 on March 15, 2025 — but how old are they on March 14, 2025? Exactly 24 years, 11 months, and 29 days. This calculator counts completed years first, then remaining months, then remaining days — the same method used on legal documents and in most countries worldwide.
Month lengths vary (28–31 days), so the "days" component of an age always refers to remaining days after full months are counted, not a fixed 30-day approximation.
Frequently Asked Questions
What if I was born on February 29 (a leap day)?
In non-leap years, February 29 birthdays are conventionally observed on February 28 or March 1 depending on jurisdiction and personal preference. Most countries legally treat February 28 as the birthday for official purposes. This calculator uses February 28 as the equivalent in non-leap years.
Why is my age shown differently in some Asian countries?
In traditional East Asian age reckoning (used historically in Korea, China, and Japan), a person is considered 1 year old at birth and gains a year on New Year's Day rather than their birthday. This calculator uses the international (Western) system where age increases on the birthday.
Can I calculate the age difference between two people?
Yes. Use the Between Dates tab and enter both people's birth dates. The result shows the exact time difference in years, months, and days — which is the age gap between them.
What common uses are there for a date difference calculator?
Common uses include calculating how long until an event (vacation, retirement, wedding), how long ago something happened (employment start date, diagnosis date), contract or warranty duration, project timelines, and legal or financial deadlines.