Years
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Free · Instant · No signup
Age Calculator
Exact years, months, days, and hours.
Age Calculator
Age calculator
Age breakdown
Months
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Days
0
Total days lived
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Years, months, days for forms and milestones
Insurance forms ask age as of policy date. School enrollment uses age on September 1. This calculator splits the span into years, months, days plus total days lived.
Default birth June 15, 1990 with today as reference shows live totals on load. Optional "as of" overrides today for planning.
Copy exports birth, reference, breakdown, and total days.
Pair with date span and health tools
Days between two arbitrary events (not from birth) belong in the Date Difference Calculator.
Scheduling across zones after you know the calendar date: Time Zone Converter.
Calorie planning by age band often starts with the BMR and TDEE Calculator, not this page alone.
Rerun when the reference date moves
Birthday morning rerun is the social media screenshot moment. Policy anniversary rerun is the compliance moment.
Leap day births: civil date Feb 29 uses standard calendar borrowing; some jurisdictions pick Feb 28 or Mar 1 for non-leap years. This tool uses the date you type.
Total days is useful for dev milestones ("10000 days old") even when years is the headline number.
Frequently Asked Questions (FAQ)
How is age calculated?
Years, months, and days from birth date to a reference date (default today). Borrowing adjusts when day or month would go negative. Total days = floor difference in UTC midnight dates.
Can I use a future reference date?
Yes. Pick any "as of" date on or after birth. Useful for "how old will they be on wedding day" planning.
What if reference is before birth?
Blocked with alert. Reference must be on or after date of birth. Copy disabled.
Does timezone affect age?
Date inputs use calendar dates without time-of-day. For birth near midnight across zones, use the civil date on the birth certificate.
Related tools
- Date Difference Calculator Days between two dates.
- Time Zone Converter Convert times across city offsets.
- BMR and TDEE Calculator Mifflin-St Jeor BMR, TDEE, 20% loss and 15% surplus calorie targets.
- Daily Water Intake Calculator Daily water from weight, exercise minutes, and climate, in oz, liters, or cups.