About this Age Calculator
Age Calculator gives a calendar-based age between a birth date and a selected comparison date. It separates the result into completed years, months and days instead of simply dividing a total day count by 365.
Formula or method
The tool compares calendar components so month lengths and leap years are handled as calendar dates rather than an average number of days.
Example
Choose a date of birth and a comparison date to see completed years plus the remaining months and days.
Common uses
- Check a current age from a date of birth.
- Find someone’s age on a past or future date.
- Verify age intervals for records or planning.
How to use this tool
- Enter the values or text requested by the calculator.
- Choose units or options when the tool provides them.
- Select the calculation button and review the result.
- Use the formula, example and notes on this page to check whether the result fits your situation.
Important note
The default comparison date is today, but you can choose another date for historical or future age calculations.
Frequently asked questions
Does it account for leap years?
Yes. The calculation uses real calendar dates rather than assuming every year has the same number of days.
Can the comparison date be in the past?
Yes, as long as it is not before the date of birth.