Age Calculator

How to Use This Tool

Enter your birth date (and today’s date if needed), then calculate to see your age.

When Should You Use This Tool?

Use this for forms, eligibility checks, birthdays, or quickly confirming age without manual counting.

Steps

1. Enter your birth date.
2. Click calculate.
3. Read the result.

See also: Countdown Timer, GSM/UTC Time Converter .

How old am I exactly?

Pick your birth date in the date picker and click "Calculate Age": the tool shows your age as of today in years, months and days, plus the total number of months, weeks and days you have lived. The date picker stops at today's date, since a birth date cannot be in the future.

The result has four lines:

• Years, months, days: your age in the way people normally say it, for example 35 years, 6 months, 23 days.
• Total months: completed years times 12, plus the extra months.
• Total weeks: total days divided by 7, rounded down to whole weeks.
• Total days: the number of full days between your birth date and now.

How is age calculated in years, months and days?

Age is counted in completed units: first full years, then full months since your last birthday, then the days left over. The calculator subtracts the birth year, month and day from today's year, month and day. When the day part comes out negative, it borrows one month and adds the length of the previous month. When the month part comes out negative, it borrows one year and adds 12 months.

Worked example: someone born on August 15, 1990, checking on March 10, 2026.

1. Raw difference: 2026 minus 1990 is 36 years, March minus August is minus 5 months, 10 minus 15 is minus 5 days.
2. The days are negative, so borrow a month: minus 6 months, and minus 5 plus 28 (February 2026 has 28 days) gives 23 days.
3. The months are negative, so borrow a year: 35 years, and minus 6 plus 12 gives 6 months.
4. Result: 35 years, 6 months, 23 days, which is 426 total months.

You can check it by counting forward: August 15, 2025 was the 35th birthday, February 15, 2026 is 6 months later, and from there to March 10 is 23 days.

How does the age calculator handle a leap-year birthday?

If you were born on February 29, the calculator treats March 1 as your birthday in years that have no February 29. On February 28 of a common year you are still one day short of the next year of age, and on March 1 the year ticks over. In leap years, your birthday is February 29 as usual. The table below shows this and a few other edge cases:

Legal rules for when someone born on February 29 officially turns a year older differ between countries, with some using February 28 and others March 1. If an age cutoff matters for a contract, a license or a benefit, check the rule where you live.

How many days old am I?

Look at the "total days" line: it counts every full day from your birth date up to now, including the extra day in each leap year. As a rough guide, one year is about 365.25 days, so a 30 year old has lived roughly 10,950 days, and a 10,000 day milestone arrives about 27 years and 4 months after birth. The "total weeks" line is that same figure divided by 7 and rounded down, which is handy for tracking a baby's age in weeks.

What do people use an age calculator for?

Mostly for questions where the exact number matters and mental math gets it wrong by a year:

• Forms and applications: most forms ask for age in completed years, which is the first number in the result.
• Eligibility cutoffs: school entry, sports age groups, retirement plans and age-restricted services often depend on whether a birthday has passed yet.
• Babies and toddlers: parents and doctors often talk about age in months or weeks, both of which the tool shows directly.
• Milestones: spotting a 1,000th week or 10,000th day birthday from the totals.

The calculator always measures up to today. To find the time between two other dates, such as someone's age on a past event, use the date difference calculator instead.