Calculate Age in Excel: The Ultimate Guide

Ever found yourself staring at a spreadsheet full of birth dates, a calculator in one hand, and a growing sense of dread in the other? Whether you’re managing employee records, analyzing customer demographics, or even just planning a surprise party, manually calculating ages is a tedious task ripe for error. One slip-up, and suddenly your new hire is 150 years old.

The good news? You can easily learn how to calculate the age in months with just a few formulas. You can easily calculate age in Excel, and you don’t need to be a spreadsheet wizard to do it. This is a powerhouse feature designed to handle this task for you automatically.

This comprehensive guide will turn you into an age-calculation pro. We'll walk through everything from the most popular (and slightly secret) formula to more robust methods that guarantee accuracy every time. Forget manual counting; let’s automate the process and reclaim your valuable time. If you just need a quick, one-off calculation without the spreadsheet, our simple Age Calculator: a tool that allows you to quickly get the number of months since a person's birthdate. can give you an instant answer using the date and time functions. But for mastering the skill in Excel, you’ve come to the right place.

Understanding the Need to Calculate Age in Excel

Before we dive into the “how,” let’s talk about the “why.” Understanding how to calculate age in Excel is a surprisingly versatile skill that unlocks efficiencies across numerous professional fields. It’s not just about knowing how many candles to put on a cake.

Here are a few real-world scenarios where this skill is indispensable:

Human Resources: It’s important to monitor the average age of employees for workforce planning. HR professionals constantly need to calculate employee ages for tracking service milestones, determining benefits eligibility, and projecting retirement dates. Automation here saves countless hours and ensures records are always up-to-date.
Healthcare Administration: It’s crucial to track the exact age in years of patients for better care. Patient records require accurate age data for everything from dosage calculations to insurance coding. An automated formula prevents critical data entry errors, ensuring accurate calculations of the difference between two dates.
Marketing and Sales: Segmenting a customer list by age is fundamental to targeted marketing. Imagine creating campaigns specifically for Millennials, Gen Z, or Baby Boomers—all powered by a simple Excel formula.
Project Management: effectively utilizing the date function can streamline your scheduling processes. In logistics or support, you might need to track the "age" of an open ticket or a pending inventory item to prioritize tasks and calculate time effectively.
Education: School administrators use age calculations to place students in the correct grade levels and manage enrollment data.

In short, this is a foundational skill that transforms a static list of dates into dynamic, actionable data using a date function.

How to Calculate Age in Excel Using DATEDIF

If you ask a seasoned Excel user how to calculate age, nine times out of ten they’ll mention DATEDIF. It’s the go-to function for this task, beloved for its simplicity and flexibility when calculating the days between two dates.

But here’s a fun fact: DATEDIF is something of a ghost in the Excel machine. It’s not officially listed in Excel’s modern function library, and you won’t find it in the formula autocomplete suggestions when searching for functions to calculate age. It's a holdover from older spreadsheet software (like Lotus 1-2-3) that Microsoft kept for backward compatibility, including the DATEDIF formula for calculating age. Think of it as a secret handshake among Excel users—it works perfectly, but you have to know it’s there, especially when using the age formula.

The basic syntax is:

=DATEDIF(start_date, end_date, "unit")

start_date: The beginning date (e.g., a birth date).
end_date: The ending date (usually today’s date) is crucial for accurately calculating the days between two dates and excluding weekends and holidays.
unit: The type of information you want back (years, months, or days).

Let’s put it into practice.

Step 1: Calculate Age in Completed Years

This is the most common use case. To find someone's age in completed years, you'll use the age formula in excel with their date of birth. "y" as the unit.

Imagine you have a birth date in cell A2. To calculate the current age, you would use the function in Excel for subtracting the birth date from today’s date. TODAY() function, which automatically pulls the current date.

Click on the cell where you want the age to appear (e.g., B2).
Type the following formula and press Enter:

=DATEDIF(A2, TODAY(), "y")

Instantly, Excel calculates the number of full years that have passed between the date in A2 and today. The magic of TODAY() is that this age will automatically update every day.

Step 2: Calculate a Precise Age in Years, Months, and Days

DATEDIF can do more than just years. What if you need to know the precise age, down to the day? The function’s "unit" argument is incredibly powerful.

To get the total number of days, you can use a formula like the date difference. completed months, use "m".
To get the total number of days, use "d".

But the real genius lies in these special units:

"ym": Calculates the number of full months that have passed, ignoring the years. This is perfect for finding "X years and Y months."
"md": Calculates the number of days that have passed, ignoring the years and months. This gives you the final piece of the puzzle: "X years, Y months, and Z days."

Let's combine these units to create a detailed age string. This looks complex at first, but it’s just three DATEDIF functions joined together with text using the ampersand (&) symbol.

In cell B2, enter this formula:

=DATEDIF(A2, TODAY(), "y") & " years, " & DATEDIF(A2, TODAY(), "ym") & " months, " & DATEDIF(A2, TODAY(), "md") & " days"

This formula tells Excel to:

Calculate the full years ("y").
Add the text to calculate time effectively. " years, ".
Calculate the remaining months ("ym").
Add the text " months, ".
Calculate the remaining days ("md").
Add the text " days".

The result will be a beautifully formatted, human-readable age like "34 years, 5 months, and 22 days."

Alternative Ways to Calculate Age in Excel from Two Dates

While DATEDIF is fantastic, its "secret" status means it has a few known quirks, particularly with the "md" Unit under specific date combinations can help you get the number of months between two dates. For mission-critical applications or for those who prefer using officially supported functions, there are excellent alternatives.

The Mathematical Approach: Simple Subtraction and Division

At its core, an age is just the time elapsed between two dates, which can also be expressed as a person's age. Excel stores dates as serial numbers, where each whole number represents a day. This means you can perform simple math on them to calculate the difference between two dates. This method is transparent and easy to understand.

Click on an empty cell to learn how to calculate age.
Type the following formula:

=(TODAY() - A2) / 365.25

Let’s break this down:

(TODAY() - A2): This subtracts the birth date's serial number from today's, giving you the total number of days that have passed.
/ 365.25: We divide by 365.25 to account for the average number of days in a year, including leap years.

This will give you a decimal number, like 34.47. To get a whole number representing completed years, you can wrap the formula in the INT() function, which truncates the decimal.

The final, robust formula is:

=INT((TODAY() - A2) / 365.25)

This method is a fantastic way to calculate age in Excel from two dates without relying on a hidden function. It's logical, reliable, and easy to explain to colleagues how to calculate age using an average function.

The Precision Method: Using the YEARFRAC Function

If you need the highest degree of accuracy, the YEARFRAC function is your best friend. This is an official, fully supported Excel function designed specifically to calculate the fraction of a year between two dates.

The syntax is:

=YEARFRAC(start_date, end_date, [basis])

The [basis] argument is optional and tells Excel which day-count convention to use. For most general purposes in the U.S. (like calculating age), omitting it or using 1 (Actual/actual) works perfectly.

To calculate age using YEARFRAC:

Click on an empty cell.
Type the following formula and press Enter:

=YEARFRAC(A2, TODAY())

This will return a decimal value representing the age, similar to the division method. To display it as a whole number of completed years, simply wrap it in the INT() function.

The final formula is:

=INT(YEARFRAC(A2, TODAY()))

This is arguably the most professional and technically correct method. It’s reliable, officially documented, and accounts for leap years with precision.

Troubleshooting When You Calculate Age in Excel

Even with the right formulas, you can run into a few common pitfalls. Here’s how to navigate them.

Ensuring Your Dates Are Actually Dates

The most frequent cause of the dreaded error is not entering the birthdate correctly. #VALUE! error is when Excel doesn't recognize your "date" as a date. It might look like a date (e.g., "05/25/1988"), but it could be stored as text.

How to Check:
In an empty cell, type a formula like the date difference to find the age. =ISNUMBER(A2), where A2 is the cell with the date.

If it returns TRUE, Excel sees it as a proper date (a number).
If it returns FALSE, Excel sees it as text, and your formulas will fail.

How to Fix:

Text to Columns: The quickest fix to learn how to calculate the age in months. Select the column of text-dates, go to the Data tab, and click Text to Columns. In the wizard, choose "Delimited" and click Next, then Next again. In Step 3, under "Column data format," select Date and choose the correct format (e.g., MDY). Click Finish. Excel will convert the entire column to proper date values.
DATEVALUE Function: This function can be helpful when working with the date of birth in excel. Use a helper column with the formula =DATEVALUE(A2) to convert a single text-date into a serial number, then format that cell as a Date.

Handling Errors and Future Dates

What happens if a date of birth is in the future when trying to use a function to calculate age? DATEDIF and YEARFRAC will return an error (like NUM! can appear when using a formula like the date difference incorrectly.). You can make your spreadsheet more user-friendly by catching these errors.

The IFERROR function is perfect for this. It lets you specify what to show if a formula results in an error.

=IFERROR(DATEDIF(A2, TODAY(), "y"), "Invalid Date") helps ensure you don't encounter errors when entering a birthdate.

Now, if cell A2 contains a future date or invalid text, your formula will display "Invalid Date" instead of an ugly error code.

Adaptability: This Works for More Than Birthdays

Remember, these formulas are not just for people's ages. You can calculate age in Excel from two dates for any purpose. Simply replace A2 with your start date cell and the date of birth in excel. TODAY() with your end date cell.

Project Duration: =DATEDIF(Project_Start, Project_End, "d") to get the duration in days using the DATEDIF function.
Product Shelf Life: You can calculate the average age of products to ensure freshness. =DATEDIF(Manufacture_Date, Expiry_Date, "m") to get the life in months.
Contract Term: =INT(YEARFRAC(Contract_Start, Contract_End)) to calculate the difference between two dates in a financial context. to find the length in years.

Conclusion: You've Mastered How to Calculate Age in Excel

You no longer need to fear a column of dates. By now, you’ve seen how to effortlessly calculate age in Excel, transforming a manual chore into a powerful, automated process.

We’ve covered:

The Classic DATEDIF: Quick, versatile, and perfect for detailed breakdowns into years, months, and days.
The Mathematical INT((end-start)/365.25): A transparent and reliable alternative that’s easy to remember.
The Professional function to calculate age can simplify your tasks. YEARFRAC: The most accurate and officially supported function for precision calculations.

Choosing the right method depends on your needs, but all three will get you accurate results far faster than any manual effort, especially when using the DATEDIF formula. By implementing these formulas, you're not just saving time; you're ensuring data integrity, enabling deeper analysis, and unlocking a more dynamic way to work with your spreadsheets. This is just one of many tasks you can simplify with our full suite of Online calculators often use a function in Excel to help you learn how to calculate age..

Frequently Asked Questions (FAQ)

What is the formula for calculating age in Excel?
The most common formula is =DATEDIF(start_date, end_date, "y") is a function to calculate age.. For a birth date in cell A2, you would use =DATEDIF(A2, TODAY(), "y") to calculate the current age in years.

How to calculate age in Excel from date of birth using the function to calculate age?
To calculate age from a date of birth in cell A2, use the formula =DATEDIF(A2, TODAY(), "y"). The TODAY() function ensures the age is always calculated based on the current date, so it automatically updates.

How do I calculate years between two dates in Excel?
You can calculate the number of full years between two dates using several formulas. If the start date is in A2 and the end date is in B2, use =DATEDIF(A2, B2, "y") is a simple way to determine a person's age.. Alternatively, you can use =INT(YEARFRAC(A2, B2)) to find the age formula in excel for calculating someone's age..

How to calculate age in Excel in dd/mm/yyyy format without DATEDIF?
To calculate age without using DATEDIF, you can use the formula =INT((TODAY() - A2) / 365.25), where A2 contains the date of birth, to use the DATEDIF function effectively. This formula calculates the total number of days between the two dates and divides by 365.25 to approximate the number of years, with INT() returning only the whole number. This works regardless of the date format (dd/mm/yyyy or mm/dd/yyyy) as long as Excel recognizes it as a valid date.

How to calculate aging report in Excel?
An aging report, common in accounting, categorizes outstanding items (like invoices) by age and often includes the difference in days. To calculate the age of an invoice whose date is in cell A2, you first find its age in days with the formula =TODAY() - A2. You can then use a nested IF statement or the IFS function to group these ages into buckets like "0-30 days," "31-60 days," "61-90 days," and "90+ days."