Age Calculator
Find your exact age in years, months, and days. Enter a date of birth and optionally choose the date you want the age calculated for.
Enter your date of birth to calculate your age.
Next step: Retirement Date Calculator
When to use this calculator
Use this calculator whenever you need an exact age—in years, months, and days—rather than a rough year count, or when you need to know how old someone was on a past date or will be on a future one.
Exact current age
Find your precise age today, down to the month and day.
Age on a past event date
Check exactly how old someone was on a graduation, wedding, or other historical date.
Age on a future date
Confirm the exact date someone reaches a milestone age—pair with the Retirement Date Calculator for retirement-age planning specifically.
General duration instead
For any two dates that aren't a birth date and today, use the Date Duration Calculator directly.
Inputs
Date of birth
The birth date to calculate age from.
As-of date (optional)
Defaults to today (UTC); set a past or future date to calculate age as of that date instead.
How the calculation works
Age is calculated on the UTC calendar: years, months, and days between your date of birth and the "age as of" date. Months and days borrow from larger units when needed, matching how ages are usually stated in everyday life.
By default, the as-of date is today in UTC. You can change it to see how old someone was on a past date or will be on a future date. The date of birth must be on or before the as-of date.
Worked example
Date of birth: 15 June 1990. As-of date: 14 July 2025.
Result: 35 years, 0 months, 29 days.
The birthday (15 June) has already passed this year as of 14 July, so the year count has incremented and the remaining figure is the partial month since the birthday.
Edge cases
Birthday today
If today is your birthday, years increase by one and months and days reset to 0 (for example, 30 years, 0 months, 0 days).
End of month birth date
Born on January 31 and as-of March 28? The calculator uses calendar months, so partial months reflect real month lengths.
29 February birthdays
A birth date of 29 February only recurs on true anniversaries in leap years; the age calculation still resolves correctly in non-leap as-of years using calendar-month math.
Historical as-of date
Set as-of to a past event (such as a graduation date) to see exactly how old someone was on that day.
Related Date & Business Days Calculators
The Business Days vs Calendar Days Guide explains when weekends and holidays count and which day type applies to deadlines, invoices, and contracts.
The How Business Days Are Calculated Guide and Business Days Between Dates Guide cover the counting rules behind every business-day tool on this site.
The Business Days Calculator and Working Days Calculator count weekdays between two known dates, excluding weekends and optional US federal holidays.
The Add Business Days To Date, Subtract Business Days From Date, and Business Day Offset calculators move a single date forward or backward by a business-day count.
The Business Days Until Date Calculator counts business days remaining from today or a custom date to a target deadline.
The Days Between Dates Calculator counts every calendar day between two dates, including weekends—use it instead of the business-day tools when weekends should count.
The Date Range Calculator and Date Duration Calculator break a range into calendar-day totals or a years/months/days breakdown, with inclusive or exclusive boundary options.
The Add or Subtract Days Calculator shifts a single date forward or backward by days, weeks, or months.
The Age Calculator applies the same calendar breakdown used by Date Duration to a birth date, expressed as years, months, and days.
The Hours Between Dates and Date Difference calculators measure elapsed time between two date-times down to hours, minutes, and seconds.
The Date Format Converter, Unix Timestamp Converter, and Timezone Converter handle format and zone conversion for a single instant rather than a span between two dates.
FAQ
- Why UTC for age?
- Date-only fields use UTC midnight so everyone sees the same age for the same birth date and as-of date, without local midnight shifting the calendar day.
- Can the as-of date be before birth?
- No. If the as-of date is earlier than the date of birth, the calculator shows zero years, months, and days.
- How is this different from days between dates?
- Days Between counts a single span in days. Age breaks that span into years, months, and days the way people describe age in conversation.
- How is this different from the Date Duration Calculator?
- Same underlying calendar-breakdown engine, framed specifically for a date of birth and an as-of date. Use the Date Duration Calculator directly for any other pair of dates.
Related Guides
Browse all Date & Business Days
Similar Tools
- Retirement Date CalculatorFind the exact date you reach a target retirement age from your date of birth, with current age and time remaining.
- Employment Duration CalculatorFind exact length of service in years, months, and days from a joining date to today or a last day of employment.
- Days Between DatesCalculate the number of days between two calendar dates.
- Business Days CalculatorCount working days between dates, excluding weekends.
- Add or Subtract DaysShift a date forward or backward by days, weeks, or months.
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