Age Calculator
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Age Calculator by Date of Birth

Calculate your exact age in years, months and days with our free online age calculator. Enter your date of birth to find your chronological age, total days, total weeks, total months, and next birthday — instantly and accurately.

Whether you want to know how old am I, calculate my age from date of birth on today's date, or use it as a child age calculator or baby age calculator, this tool gives you a clear, professional and easy-to-understand result every time.

Exact Age Years, Months & Days Total Days & Weeks Next Birthday Child & Baby Age

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Exact

Calendar Age

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Calculate Your Exact Age

Calculations: 26

Enter your date of birth to get your exact age.

Enter your birth date or use the calendar.

Today or any date. You can also use the calendar.

Calculate age on:

What Is an Age Calculator?

An age calculator is an online tool that determines the amount of time between a person's date of birth and a selected date. Instead of manually counting calendar years, months and days, an age calculator online performs the calculation for you and presents the result in a clear, easy-to-understand format.

Our age calculator by date of birth works as a complete chronological age calculator: it can calculate your age in years, months and days, and also show the total number of months, weeks and days that have passed since your date of birth.

Use this online age calculator to answer questions such as “How old am I?”, calculate your age today, calculate age from date of birth on any date, or find your age on a particular date in the past or future.

What Can This Age Calculator Calculate?

Get more than just your age. Our age calculator by DOB provides several useful date and age calculations in one place.

Exact Age in Years, Months & Days

Find your exact chronological age instead of an approximate number of years.

Age Calculator by DOB

Enter your date of birth to calculate your age from date of birth quickly and accurately.

Age Calculator by Date

Choose a past, present or future date to find out how old you were, or will be, on that date.

Total Days Lived

See the total number of days between your birth date and the selected calculation date.

Total Months & Weeks

View your age as total months and total weeks in addition to years and days.

Next Birthday Countdown

Find the date of your next birthday and see how many days remain until it arrives.

Child Age Calculator

Use it as an age calculator of child to track a young child's exact age in years, months and days.

Baby Age Calculator

Works as a baby age calculator too, showing an infant's age in the most useful detail for parents.

Age Calculator on Today

Defaults to today's date automatically, so you always get an age calculator on today's date result by default.

How to Use the Age Calculator

Calculating your age from date of birth takes only a few seconds.

1

Enter Your Date of Birth

Select your day, month and year of birth in the date of birth field.

2

Choose the Calculation Date

Leave the date as today for an age calculator on today's date, or select another date to calculate your age by date on a specific day.

3

View Your Exact Age

Click Calculate My Age to see your age in years, months and days along with additional statistics.

Common Uses for an Age Calculator

An online age calculator can be useful for everyday situations, personal planning and checking dates. You can use it to calculate age from date of birth, check your age today, or determine your age on a specific date using our age calculator by date feature.

Parents can also use this tool as an age calculator of child or age calculator of baby to determine the age of a child or infant. For younger children, expressing age in years, months and days can be more useful than simply stating the number of completed years — which is why our baby age calculator breaks results down to the day.

You can also use the calculator when you need to compare dates, prepare personal records, plan birthday events, or simply find the answer to “How old am I?” right now.

What Is Chronological Age?

Chronological age is the amount of time that has passed from a person's date of birth to a particular date. It is normally expressed in completed years, but a true chronological age calculator can also calculate it more precisely using years, months and days.

For example, someone may be 25 years old, but their exact chronological age could be 25 years, 4 months and 12 days. This age calculator by date of birth provides that more detailed result automatically.

How Is Age Calculated? (Age Calculator Formula)

At a basic level, age is calculated by comparing the date of birth with the date on which the age is being calculated. The age calculator formula first determines the difference in calendar years, then adjusts the months and days to produce the final chronological age.

Basic age calculation:

Calculation Date − Date of Birth = Elapsed Time

Because calendar months have different numbers of days, an exact age calculation needs to account for the actual calendar dates rather than simply dividing the number of days by a fixed number.

Age Calculator Formula in Excel

If you prefer to build your own age calculator in Excel, the most common approach uses the DATEDIF function to compare a birth date cell with today's date:

=DATEDIF(B2, TODAY(), "Y") & " years, " & DATEDIF(B2, TODAY(), "YM") & " months, " & DATEDIF(B2, TODAY(), "MD") & " days"

In this example, cell B2 holds the date of birth. This Excel age calculator formula returns the exact age in years, months and days, similar to the result produced by our online age calculator by date of birth.

Important Information About Age Calculations

Age calculations are based on calendar dates. The result can therefore differ from a simple calculation based only on the number of days divided by 365.25. Leap years and the different lengths of calendar months are considered when determining the years, months and days portion of your age.

This tool is intended for general informational and personal date calculations. For legal, medical, financial or official eligibility requirements, always use the rules and dates specified by the relevant authority.

Frequently Asked Questions About Age Calculators

How can I calculate my age from my date of birth?

Enter your date of birth into the calculator, choose the date you want to calculate your age on, and click Calculate My Age. The calculator will show your exact age in years, months and days.

How does an age calculator by DOB work?

An age calculator by DOB compares your date of birth with a selected calculation date. It accounts for calendar years, months and days to provide your chronological age.

Can I calculate my age on a specific date?

Yes. Select any valid calculation date that is on or after your date of birth. This age calculator by date feature lets you find your age on a past, current or future date.

Can I use this as a chronological age calculator?

Yes. The calculator provides chronological age based on the difference between your date of birth and the selected calculation date.

Can I use this as an age calculator of a child or baby?

Yes. Parents and caregivers can enter a child's or baby's date of birth to calculate their age. For infants and young children, the years, months and days result can provide more useful detail than completed years alone.

Does the calculator show total days, weeks and months?

Yes. After calculating your age, the result includes the total number of days and also provides total weeks, months and years.

Is this online age calculator free?

Yes. You can use this age calculator online by date of birth without installing software or downloading an application.

What is the difference between age in years and exact age?

Age in years usually refers to completed years, while exact age can include the remaining months and days. For example, a person can be 30 years old and have an exact chronological age of 30 years, 5 months and 10 days.

Can I build an age calculator formula in Excel myself?

Yes. Excel's DATEDIF function can calculate age in years, months and days from a date of birth cell, giving a result similar to this online age calculator by date of birth. See the Age Calculator Formula section above for an example formula.

Calculate Your Exact Age

Use our free age calculator by date of birth to find your chronological age in years, months and days, calculate total days and weeks, and see your next birthday.

Calculate My Age