Age Calculator
Enter a date of birth to get an exact age in years, months and days as of today or any other date.
How to use the age calculator
- Enter the date of birth.
- Optionally change the “calculate age as of” date — it defaults to today.
- Click Calculate age to see the exact breakdown.
Features
- Exact years, months and days, accounting for varying month lengths
- Totals in days, weeks and months
- Calculate age as of any date, not just today
Why calendar age differs from a simple day count
An exact age is based on calendar boundaries rather than dividing the number of days by 365. Month lengths vary, and leap years add an extra day, so a calendar-aware calculation is the reliable way to express years, months and days.
The comparison date is useful for forms, school admissions, eligibility checks and future dates. If a form asks only for completed years, use the year value from the result; if it asks for exact age, keep the full years–months–days breakdown.
Frequently asked questions
Related tools
Using an age result correctly
For forms and eligibility checks, the important detail is the reference date. Someone’s age today can be different from their age on an application deadline, exam date or policy renewal date, so change the “as of” date when the rule is date-specific.
- Use the birth date exactly as it appears on the official record.
- For age limits, calculate on the deadline date rather than today.
- If a policy treats leap-day birthdays specially, follow that policy rather than a generic calendar result.
Related reading: How to use online calculator results responsibly