Age Calculator
Calculate your age from your date of birth (DOB) in years, months, and days. See how old you are today, or find your chronological age on any past or future date.
What this calculator does
The Age Calculator estimates your result instantly from the values you enter, using standard date & time formulas. Calculate your age from your date of birth (DOB) in years, months, and days. See how old you are today, or find your chronological age on any past or future date. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.
Result
About Age Calculator
The Chronological Age Calculator reports age with the precision often needed for assessments and records: exact years, months, and days, plus the same span converted to total months, weeks, and days.
Leave the As Of Date blank to use today, or set it to any reference date you need.
Formula & Mathematical Calculation
birth = new Date(braw + 'T00:00:00')
years = asof.getFullYear() - birth.getFullYear()
Derived directly from the verified calculation function in the tool engine.
Calculation Example
With a birth date of 15 January 2010 and an as-of date of 20 April 2024:
- Exact age: 14 years, 3 months, 5 days
- Total months: 14 × 12 + 3 = 171
- Total days: 5,209
- Total weeks: floor(5,209 ÷ 7) = 744
Key Benefits
- Gives exact age in years, months, and days for assessments and records
- Also converts the span into total months, weeks, and days
- Lets you set any as-of date or default to today
- Handles leap years when counting total days
How to Use this Calculator
-
Enter the birth date
Select the birth date in the Birth Date field. -
Set the as-of date (optional)
Choose an As Of Date to measure age to, or leave it blank to use today. -
Calculate
Press Calculate and read the Exact Age, Total Months, Total Weeks, and Total Days boxes.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
- Results use standard published formulas and account only for the values entered above.
- Rounding is applied for display; the underlying calculation uses your full precision.
- Results are returned in the same units you enter, unless the tool states the output unit.
What it does not cover
- Age Calculator produces a calculated result for reference and learning, not a certified or official measurement.
- Real-world outcomes differ when tolerances, rounding rules or local standards apply.
- Definitions and standards vary by region and change over time; verify the convention that applies to your case.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For work where the result carries real consequences, confirm it against an authoritative source.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.