How to use this calculator
The calculation compares calendar dates rather than dividing days by 365. February 29 anniversaries clamp to February 28 in non-leap years. Results also give total months, weeks, hours, minutes and seconds using date-only 24-hour days; these are not timezone elapsed-time measurements.
- Enter date of birth, age on date, february 29 birthday in non-leap years and review the remaining options.
- Select Calculate or change a value to update the result. Read the result label and units before copying.
- Use Reset to restore the worked starting values.
Formula and method
Dates have no time-zone or time-of-day component. Next birthday includes today. The selected February 29 convention applies to the birthday countdown; calendar-age components keep the documented February 28 anniversary convention.
Worked example
From June 15, 1995 to June 15, 2025 is 30 years.
Questions about age calculator
How old am I, and how many years old am I?
Your age in whole years is the number of completed birthdays between your birth date and the date you choose. Enter your date of birth in the Age Calculator and use today as the comparison date to see your current age.
How do I calculate my age from my date of birth?
Subtract your birth year from the comparison year, then subtract one if your birthday has not occurred by the comparison date. Someone born on 10 October 2000 is 24 on 9 October 2025 and 25 on 10 October 2025.
How can I calculate my age in years, months, and days?
Count completed calendar years first, then completed calendar months, then the remaining days. From 15 January 2000 to 20 March 2025, the result is 25 years, 2 months, and 5 days. Months have different lengths, so dividing total days by 30 does not give calendar age.
How do I calculate my age on a specific date?
Enter your birth date and set the comparison date to the past or future date you need. For example, a person born on 1 June 2000 will be 30 on 1 June 2030. Use a comparison date on or after the birth date.
How are leap years and February 29 birthdays handled?
The calculator counts actual calendar days, including February 29. For calendar anniversaries it clamps February 29 to February 28 in a non-leap year. This is the tool’s calculation convention; legal birthday rules can depend on the jurisdiction.
What assumptions should I check?
Dates have no time-zone or time-of-day component. Next birthday includes today. The selected February 29 convention applies to the birthday countdown; calendar-age components keep the documented February 28 anniversary convention.
Are my inputs saved?
Calculations run in your browser. We store only tool IDs for favorites and recent tools. A calculation link contains your inputs only when you explicitly choose to copy one.