Age Calculator

Use this age calculator to calculate age from your date of birth in years, months, and days—plus totals like days since birth, weeks, hours, and minutes. It’s perfect for answering “how old am I?” with clear, exact results.

Choose an optional age as of date to find your age on a past or future day (useful for forms, school cutoffs, and timelines). For more tools, visit All Calculators or browse Health & Fitness.

Everything runs locally in your browser for privacy. No sign-ups, no tracking, and no data leaves your device.

Calculate Your Exact Age

Enter your birth date using the calendar picker (YYYY-MM-DD).
Leave blank to calculate age as of today.

Results

How It Works

This calculator finds your exact age using a calendar-based approach. First, it counts full years from your date of birth up to the “as of” date, then counts full months after the last year anniversary, and finally counts the remaining days. That’s why “age in years months days” stays accurate across 28–31 day months and leap year rules.

To reduce timezone and daylight-saving surprises, dates are normalized to local noon before computing day differences. This helps prevent “off-by-one day” shifts that can happen around DST transitions. If you want more tools, explore All Calculators.

Feb 29 policy: if you were born on Feb 29, in non-leap years the birthday countdown uses Feb 28. The exact age calculation still respects the real calendar, and the chosen policy is displayed in results for transparency.

Use Cases

  • Check “how old am I” in exact years, months, and days for profiles and IDs.
  • Calculate age as of a specific date for school admissions, job requirements, or eligibility cutoffs.
  • Track a birthday countdown (days until next birthday) for planning events and reminders.
  • Find total days/weeks since birth for milestones, journals, and personal timelines.
  • Compare timelines with an “as of” date for historical records (e.g., age at graduation or relocation).

Examples

Example 1
DOB: 1998-04-12, As of: 2026-01-18 → Exact age is 27 years, 9 months, 6 days (calendar-based). Next birthday is 2026-04-12.
Example 2
DOB: 2000-02-29, As of: 2026-02-10 → Age is computed normally; for the countdown in 2026 (non-leap), the next birthday is treated as 2026-02-28.
Example 3
DOB: 2010-11-05, As of: 2026-01-18 → Exact age is 15 years, 2 months, 13 days. Totals (days/weeks/hours/minutes) are derived from whole days lived.

Common Mistakes & Quick Tips

Common Mistakes

  • Entering a DOB that is in the future compared to the “as of” date.
  • Leaving DOB empty and expecting the calculator to guess a birth date.
  • Assuming months are always 30 days (calendar months vary between 28–31).
  • Ignoring the Feb 29 policy when interpreting birthday countdown results.
  • Comparing totals (days/weeks) directly to years/months/days without understanding they’re different measures.

Quick Tips

  • Use the “as of” date to compute age on a past/future day (age as of date).
  • For best consistency, keep results interpreted as whole-day totals unless you add time-of-day data.
  • If results feel off by one day, remember DST/timezone effects—this tool normalizes dates to local noon.
  • For Feb 29 birthdays, note the countdown uses Feb 28 in non-leap years (shown in results).
  • Copy “Full Summary” when you need a clean message for forms, emails, or notes.

Accuracy, Privacy & References

Accuracy & method: Calculations run locally in your browser and use calendar-aware year/month/day logic. Day totals are computed from normalized local-noon timestamps to reduce timezone and DST edge effects.

Rounding/precision: Total days are based on whole-day differences; total hours/minutes are derived from total days (days × 24, days × 24 × 60). Exact Y/M/D is calendar-based and not approximated.

Privacy-first: No data is sent anywhere. Your dates stay on your device.

Last Updated: 2026-01-18

Sources & References
  • Gregorian calendar month lengths (28–31 days) and leap year rules.
  • Leap year definition (divisible by 4; centuries require divisibility by 400).
  • Calendar-based age calculation (years, months, days) using anniversary comparisons.

Frequently Asked Questions

What does “exact age” mean in an age calculator?
“Exact age” means the result is computed using real calendar boundaries: full years first, then full months, then remaining days. It does not assume every month is 30 days or every year is 365 days. This matters because month lengths vary (28–31) and leap years add an extra day. The calculator counts complete anniversaries and month transitions so your “age in years months days” matches how dates progress on a calendar.
Why can total days differ from years/months/days?
Years/months/days is a calendar description, while total days is a straight count of whole days between two dates. Because months and years have variable lengths, converting an age like “20 years, 1 month” into days is not a fixed multiplier. The calculator reports both so you can choose what you need: exact calendar age for forms and milestones, and total days/weeks for totals, streaks, or time-span calculations.
How does the calculator handle leap years?
Leap years are handled using standard Gregorian rules: a year is a leap year if it’s divisible by 4, except century years must also be divisible by 400. The exact years/months/days calculation naturally accounts for the extra day because it compares real calendar anniversaries. Total day counts also reflect the true number of days between the normalized dates, so ages spanning leap years will include those additional days in the totals.
What is the Feb 29 birthday policy in non-leap years?
If your date of birth is Feb 29, the calculator uses a consistent countdown policy for non-leap years: it treats the birthday as Feb 28 for the “days until next birthday” result. This prevents confusion when a Feb 29 date does not exist in a given year. The policy is shown in the results. The exact age calculation still uses calendar logic and will remain consistent across leap and non-leap years.
How do I calculate age as of a specific date?
Enter your date of birth in the DOB field, then set the “as of” date to the day you want to measure against. This is useful for eligibility checks (school cutoffs, employment rules, competitions) or historical ages (age at graduation, moving, or an event). If the “as of” date is left empty, the calculator defaults to today. If the “as of” date is earlier than your DOB, the tool will show an inline error.
Does timezone or daylight saving time affect the result?
It can, especially for total-day differences near DST changes. To reduce “off by one day” issues, this calculator normalizes both dates to local noon before computing total days. That approach is more stable than using midnight timestamps that can shift during DST transitions. The exact years/months/days result is calendar-based and remains intuitive. If you need time-of-day precision, you would need an hour/minute input, which this page keeps optional for simplicity.
Is my date of birth stored or sent anywhere?
No. The calculation runs locally in your browser using vanilla JavaScript, and your input never leaves your device. There are no network calls, no external libraries, and no tracking scripts in this widget. If you copy results, the text is copied to your clipboard only when you press a copy button. This privacy-first approach makes the calculator safe to use for quick checks without sharing personal data online.
Why am I seeing an error or no results?
Most issues come from missing or invalid input. Make sure your DOB is selected and uses the built-in date picker. If you set an “as of” date, confirm it is not earlier than your DOB, and that your DOB is not in the future relative to the “as of” date. On mobile, some browsers hide date fields if focus is blocked—tap the input again. If problems persist, press Reset and enter dates once more.

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