How to Calculate Age in Microsoft Excel with a Birthday

Calculating age in Microsoft Excel using a birthday is a straightforward process that involves three main steps: inputting the birth date, inputting the current date, and using a formula to determine the age. By following these steps, you can quickly find out how old someone is, down to the number of days.

After completing the action, Excel will display the age of the individual based on the birthday and the current date. This calculation can be useful for various purposes, such as tracking milestones, organizing events, or managing age-related data.


When it comes to crunching numbers and managing data, Microsoft Excel is the go-to software for many of us. But did you know that Excel can also help you find out how old someone is? Yes, you heard that right! Whether you’re planning a birthday party, sorting out age groups for a survey, or just curious about your own age down to the day, Excel can give you an accurate answer with just a few clicks.

This feature is particularly useful for human resource professionals, teachers, healthcare workers, and anyone who needs to keep track of ages for a group of people. Plus, it’s a handy trick for personal use, like remembering family members’ ages or calculating your own age. And let’s be honest, who doesn’t forget their age sometimes?

Now, you might be thinking, “But I’m not an Excel whiz, can I still do this?” Absolutely! This guide is designed to walk you through the process step by step, making it easy for anyone to follow along, regardless of their Excel skill level. So, let’s dive into the world of Excel and discover how you can use a simple formula to calculate age like a pro!

Step by Step Tutorial: Calculate Age in Microsoft Excel Using a Birthday

Before we get into the steps, let’s understand what we’re aiming to achieve here. We will enter a person’s birth date and today’s date into Excel, and then we’ll use a built-in Excel function to calculate the person’s age. Simple, right? Let’s get started.

Step 1: Enter the Birth Date

Enter the birth date into a cell in Excel.

When inputting the birth date, make sure to use a format that Excel recognizes, such as mm/dd/yyyy. For instance, if the birth date is January 1, 1990, you would enter 01/01/1990 into the cell.

Step 2: Enter the Current Date

Enter the current date into another cell in Excel.

You can type in the date manually or use the “=TODAY()” function, which automatically inputs the current date for you. If you choose to type it in manually, use the same date format as the birth date.

Step 3: Use a Formula to Calculate Age

Use the formula “=DATEDIF(start_date, end_date, “Y”)” to calculate the age in years.

Replace “start_date” with the cell containing the birth date and “end_date” with the cell containing the current date. The “Y” signifies that you want the result in years. For example, if the birth date is in cell A1 and the current date is in cell A2, the formula would be “=DATEDIF(A1, A2, “Y”)”.

After entering the formula, press Enter, and Excel will display the age based on the dates you’ve provided.


AccuracyExcel calculates age precisely down to the number of days, ensuring you get an exact age rather than an estimate.
Time-savingInstead of manually counting years, months, and days, Excel does the calculation instantly, saving you time and effort.
VersatilityThis method can be used for any number of individuals and is easily replicable for different datasets.


Formula ComplexityFor beginners, the formula might seem a bit complicated at first, but with practice, it becomes easier to use.
Date Format SensitivityExcel requires dates to be in a specific format to perform calculations correctly, which can lead to errors if not entered properly.
Limited by Excel VersionSome older versions of Excel may not support the DATEDIF function, limiting this method’s applicability.

Additional Information

While calculating age in Excel seems pretty straightforward, there are a couple of tips and insights that can make your life even easier. Firstly, ensure that your computer’s date and time settings are correct, as this affects the TODAY() function’s accuracy. Also, remember that leap years can slightly affect age calculations, but Excel is smart enough to account for those extra days.

Another point to keep in mind is that while we’ve focused on calculating age in years, you can also calculate age in months or days by replacing the “Y” in the formula with “M” for months or “D” for days. This can be particularly useful for more precise age requirements, like for an infant’s age or for short-term events.

Lastly, consider using conditional formatting to highlight significant ages, such as 18 for legal adults or 65 for retirement age. This visual cue can be helpful when dealing with large datasets.


  1. Enter the birth date into Excel.
  2. Enter the current date into Excel.
  3. Use the formula “=DATEDIF(start_date, end_date, “Y”)” to calculate the age.

Frequently Asked Questions

What if I need to calculate age in months or days?

Simply replace the “Y” in the formula with “M” for months or “D” for days.

Can I calculate the age for multiple people at once?

Yes, as long as each person’s birth date is in a separate cell, you can drag the formula down to apply it to multiple cells.

What should I do if I get an error with the DATEDIF function?

Double-check that the dates are in the correct format and that your Excel version supports the DATEDIF function.

Can I use this method to calculate future ages?

Yes, you can enter a future date instead of the current date to find out how old someone will be on that specific date.

Does the TODAY() function update automatically?

Yes, the TODAY() function always displays the current date whenever the worksheet is opened or recalculated.


Calculating age in Microsoft Excel using a birthday is not just a neat trick; it’s a valuable skill that can save you time and ensure accuracy when dealing with age-related data. Whether you’re a professional handling employee records or a parent planning a birthday party, mastering this technique can come in handy in more ways than one.

Remember, with Excel, age is not just a number; it’s a formula away. So next time you need to find out someone’s age, don’t start counting on your fingers; let Excel do the heavy lifting for you.

And for those who are still a bit hesitant, give it a try; you might just find yourself enjoying the process. After all, there’s something oddly satisfying about watching those numbers pop up on your screen, isn’t there?