Age Calculator
Age Calculator can determine the age or interval between two dates. The calculated age will be displayed in years, months, weeks, days, hours, minutes, and seconds.
Modify the values and click the calculate button to use
Date of Birth
Age at the Date of
About Age Calculation
How Age Is Calculated Differently Around the World Age calculation varies significantly across cultures, and our calculator follows the most widely used system—the “Western” method, where a person’s age increases on their birthday. For example: A child who is 3 years and 11 months old is considered 3 until their next birthday, when they turn 4. This system is standard in North America, Europe, and many other regions.
Alternative Age Systems East Asian Age Reckoning (Korean, Chinese, Traditional Systems) In some cultures, a person is born at age 1, and their age increases at the New Year, not their birthday. Example: A baby born one day before Lunar New Year becomes 2 years old just two days later, despite only being alive for 48 hours. Inclusive Counting (Some African & Middle Eastern Cultures) The current year is counted, so a 20-year-old is also in their 21st year of life.
Why Age Calculation Can Be Tricky Month-to-Month Variations Since months have different lengths (28–31 days), calculating age in months can sometimes be ambiguous: Example 1: From February 20 to March 20 = 1 month (clear). Example 2: From February 28 to March 31 If counting Feb 28 → March 28 = 1 month and 3 days. If treating both Feb 28 & March 31 as month-ends = just 1 month. Our calculator uses the first method (exact day count) for consistency, but both interpretations are valid. Similar situations occur with: April 30 → May 31 May 30 → June 30 Why Does This Matter? Legal & Social Events (school admissions, retirement) Medical & Developmental Milestones Cultural Celebrations (coming-of-age ceremonies) Our tool provides precise age breakdowns while acknowledging these cultural and mathematical nuances. For most users, the standard calculation will apply, but it’s helpful to understand why results might differ elsewhere!