Age Calculator

Age calculator for exact years, months, and days from your date of birth

An age calculator answers one specific question: how old are you on a particular date. The most common reason people search for this is simple and practical, such as completing a form, confirming eligibility, or checking an age requirement where “years” alone is not enough. This page is built for that everyday use case, not for legal edge cases or time zone debates.

To use it, enter your date of birth in YYYY-MM-DD format. You can leave the as-of date blank to calculate your age as of today, or enter another date to calculate your age on that day. The result is shown as an exact calendar age in years, months, and days. That output is the clearest way to represent age for normal planning because it follows the calendar, not a rough average.

In addition to the main result, the calculator also shows totals that are useful in real life. Total days is helpful when you want a single number (for example, comparing two people’s ages precisely, or tracking a milestone). Total weeks and approximate total months help when you are thinking in longer planning blocks. Finally, the next birthday countdown shows the number of days until your next birthday and the date it falls on, which is useful for reminders and time planning.

Assumptions and how to use this calculator

• This calculator treats dates as whole days (it ignores time of day). If you need to be precise to the hour, this is not the right tool.
• If you leave the as-of date blank, the calculator uses today’s date on your device.
• The “years, months, days” result is a calendar difference (it adjusts for different month lengths and leap years).
• Total weeks and total months are derived from total days (weeks = days ÷ 7, months ≈ days ÷ 30.436875). These are approximations.
• For birthdays on February 29, non-leap-year birthdays are treated as February 28 for the next-birthday countdown.

Common questions

Why does my age show different “months and days” than another website?

There are multiple ways to express the same time span. Some calculators use a simple day-count conversion (for example, days ÷ 30) and then label it as months, which produces different results. This calculator uses a calendar-based method for years, months, and days, which matches how people normally talk about age.

What date format should I use?

Use YYYY-MM-DD, for example 2004-11-03. This avoids confusion between day-month and month-day formats. If the calculator cannot read your date, it will ask you to correct it.

Can I calculate my age on a future or past date?

Yes. Enter an as-of date in the same format. This is useful for checking eligibility on an upcoming date, or calculating age at a past event. The only restriction is that the as-of date cannot be before your date of birth.

Does the result include today as a full day?

The calculator works with whole calendar days, not partial days. If your as-of date is the same as your birthday, the years-months-days result will show a clean year count with 0 months and 0 days. The total days count is based on the difference between the two dates, not on the current time of day.

How can I make the result more accurate for official or legal use?

If accuracy matters for an official process, use the same as-of date and time zone that the form or authority uses, and confirm their definition of age (some processes treat age as the number of full years only). This calculator is designed for everyday accuracy, not for jurisdiction-specific rules.