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Age Calculator

Calculate exact age from a birth date with optional as-of date. Fully client-side — no account, uploads, or remote storage.

Added Apr 18, 2026 · Updated May 1, 2026

Input

Result

Enter a value for date of birth to see your result.

How it works

Calculates exact age from a date of birth to today (or any other reference date), showing years, months, days, total days, and time until the next birthday.

Step by step

  1. 01Enter your date of birth in YYYY-MM-DD format.
  2. 02Leave 'Age as of' blank to calculate age as of today.
  3. 03The tool computes the difference in years, months, and remaining days.
  4. 04Next birthday countdown shows how many days until your next birthday.

Examples

Born 1990-01-15, as of 2026-04-18

From January 15, 1990 to April 18, 2026 is exactly 36 years and 3 months.

Inputs

Date of birth:
1990-01-15
Age as of (leave blank for today):
2026-04-18

Result

Age:
36 years, 3 months, 3 days
Note: Dates must be in YYYY-MM-DD format.

Related guides

  • How to Calculate Age from a Date of Birth

    Learn how to accurately calculate age in years, months, and days from a date of birth, how leap years affect the calculation, and common pitfalls in age.

  • Leap Years and Age Calculations

    Leap Years and Age Calculations -- Leap years exist to keep calendar years aligned with Earth’s orbit. For age in years, most software counts full calendar.

Frequently asked questions

How is age calculated exactly?

Age is calculated by counting full years since the birthdate, then full months in the remaining period, then remaining days. The 'as of' date defaults to today.

Can I calculate age for a past or future date?

Yes — use the 'Age as of' field to specify any reference date instead of today.

How are leap-day birthdays handled?

Legal and cultural rules differ by country. Software typically treats Feb 29 as existing only in leap years and may roll to Feb 28 or Mar 1 in non-leap reference years — always confirm statutory age rules for compliance use cases.

Does timezone matter for age in days?

For whole calendar days, use consistent local dates for birth and reference. Instant-based age across zones needs an explicit timezone; this tool assumes the dates you enter are already aligned to your intent.

Is this suitable for medical gestational age or insurance?

No. Clinical gestational age and legal age cutoffs can depend on time-of-day, jurisdiction, and clock rules. Use this for general life-stage math only.