Age Calculator
Calculate chronological calendar age from a birth date to any comparison date, or find the age difference between two birth dates.
Formula
Calendar age uses year/month/day boundaries, not total days ÷ 365. February 29 birthdays are observed on February 28 in non-leap years.
Assumptions
- Dates use UTC calendar normalization.
- February 29 birthdays are observed on February 28 in non-leap years.
- Birth dates are not stored — all calculation happens in your browser.
Limitations
- Calendar age differs from simple day-count division by 365.
- Does not account for time zones within a calendar day.
Worked example
Born Jan 15, 1990 — age on Jul 23, 2026
Calendar age: 36 years, 6 months, 8 days.
Frequently asked questions
How are leap-day birthdays handled?
If you were born on February 29, this calculator observes your birthday on February 28 in non-leap years. The convention is stated in the results.
Is this a medical or developmental age assessment?
No. This is a calendar calculation only — not medical, developmental, or biological age.
Last reviewed: 2026-07-23
Category: Date & Time
Results are provided for informational purposes only and may not reflect real-world policies, fees, or individual circumstances.
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