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How to Use the Age Calculator
The Age Calculator can determine the age or interval between two dates. Select your date of birth using the calendar or quick-pick presets, then choose the reference date you want to calculate age as of. The calculated age is displayed in years, months, weeks, days, hours, minutes, and seconds — updated instantly as you change either date.
How Age Is Calculated
In most Western countries, age increases on a person's birthday. For example, someone born on August 31, 2000, turns 26 on August 31, 2026. This is the most common age system used for legal documents, school enrollment, and employment.
This calculator uses calendar-based counting: it accounts for leap years and varying month lengths so the year-month-day breakdown stays accurate. Total days, weeks, hours, minutes, and seconds are computed from the exact time difference between the two dates at midnight local time.
Age Systems Around the World
Some cultures count age differently. In parts of East Asia, traditional age reckoning adds one year at birth and another on New Year's Day rather than on the birthday. Under that system, a person can be one or two years older than their Western age.
South Korea officially adopted the international age system in June 2023, aligning legal age with the birthday-based method used in most of the world. This calculator follows the international (birthday-based) standard.
Frequently Asked Questions
- How do I calculate my age from my date of birth?
- Enter your date of birth and the reference date (usually today). The calculator finds the exact difference in years, months, days, weeks, hours, minutes, and seconds between the two dates.
- Can I calculate age as of a past or future date?
- Yes. Change the "Calculate as of" date to any day on or after your birth date to see how old you were or will be on that specific date.
- How is age in years, months, and days calculated?
- The tool subtracts the birth date from the reference date, adjusting for months with different numbers of days. If the day of the reference date is before the birth day, it borrows from the month count.
- Is this age calculator free to use?
- Yes. Hemiley's age calculator is completely free, runs in your browser, and does not require sign-up or upload any personal data.
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