Excel Formula Months Between Dates

adminEdit By nancy sherif29 March 2023Last Update :

Unlocking the Power of Excel: Calculating the Months Between Dates

Microsoft Excel is a powerhouse when it comes to data analysis and management. One of the many tasks Excel excels at is calculating the time interval between two dates. This can be particularly useful in various business scenarios, such as tracking project timelines, analyzing financial data, or managing inventory. In this article, we will delve into the different formulas and functions that allow users to calculate the number of months between two dates in Excel.

Understanding Date Functions in Excel

Before we jump into the specifics of calculating months between dates, it’s important to understand how Excel handles dates. Excel stores dates as serial numbers where each number represents a day. The count starts from January 1, 1900, which is serial number 1. This system allows Excel to perform date-related calculations by simply manipulating these numbers.

Basic Date Functions

Excel offers a variety of functions to work with dates, such as TODAY() and NOW(), which return the current date and the current date and time, respectively. Functions like DAY(), MONTH(), and YEAR() extract the corresponding parts from a given date. Understanding these functions is crucial as they form the building blocks for more complex date calculations.

Calculating Months Between Dates: The DATEDIF Function

The primary function for calculating the difference between two dates in Excel is DATEDIF. This function is somewhat of a hidden gem, as it is not documented in Excel’s Function Wizard. However, it is incredibly useful for calculating the difference in days, months, or years between two dates.

=DATEDIF(start_date, end_date, "M")

The “M” in the formula represents the interval type, which in this case is months. The DATEDIF function can also calculate the difference in days (“D”) or years (“Y”).

Examples of DATEDIF in Action

Let’s consider a practical example. Imagine you have a project start date of January 1, 2021, and an end date of August 31, 2021. To calculate the number of months between these two dates, you would use the following formula:

=DATEDIF("1/1/2021", "8/31/2021", "M")

This formula would return a result of 7, indicating that there are 7 months between the two dates.

Going Beyond Whole Months: The EDATE and EOMONTH Functions

Sometimes, you may need to calculate the number of months between dates, including partial months. For this, Excel provides the EDATE and EOMONTH functions.

Using EDATE for Month Increments

The EDATE function is used to add a specified number of months to a date, which can be helpful when you want to project future dates based on a monthly cycle.

=EDATE(start_date, months)

For instance, if you want to find out what the date will be 6 months after January 1, 2021, you would use:

=EDATE("1/1/2021", 6)

This would return July 1, 2021.

Using EOMONTH to Find the End of the Month

The EOMONTH function returns the last day of the month a specified number of months before or after a start date. This is particularly useful for financial calculations that depend on month-end figures.

=EOMONTH(start_date, months)

To find the last day of the month, 3 months after January 1, 2021, you would use:

=EOMONTH("1/1/2021", 3)

This would give you April 30, 2021.

Advanced Techniques: Combining Functions for Precision

In some cases, you may need to combine multiple Excel functions to achieve the desired level of precision in your calculations. For example, you might want to calculate the exact number of months and days between two dates.

Combining DATEDIF with DAY

To calculate the number of full months and additional days between two dates, you can combine DATEDIF with the DAY function.

=DATEDIF(start_date, end_date, "M") & " months and " & DAY(end_date) - DAY(EDATE(start_date, DATEDIF(start_date, end_date, "M"))) & " days"

This formula first calculates the full months between the start and end dates, then calculates the remaining days by subtracting the day of the month of the start date from the day of the month of the end date.

Case Study: Tracking Subscription Periods

Consider a business that offers monthly subscriptions. They need to track how many months have passed since each customer’s subscription start date to determine when to renew or upgrade their plans. By using the DATEDIF function, the business can automate this process and ensure accurate billing cycles.

Dealing with Edge Cases: Leap Years and More

Calculating months between dates can get tricky when dealing with edge cases like leap years or end-of-month dates. Excel’s date functions are designed to handle these scenarios, but it’s important to be aware of how they might affect your calculations.

Handling Leap Years

Leap years add an extra day to February, which can impact month calculations. Excel’s date functions account for leap years, ensuring that your calculations remain accurate regardless of the year.

End-of-Month Considerations

When calculating months between dates that include the end of a month, Excel’s functions will align the end date to the last day of the month if the start date is also the end of a month. This consistency helps avoid discrepancies in month calculations.

FAQ Section

How does Excel handle dates that are not in chronological order?

If the start date is after the end date, DATEDIF will return a negative number. It’s important to ensure that your start date is indeed the earlier of the two dates to avoid confusion.

Can Excel calculate the number of months between dates across different years?

Yes, Excel’s date functions can handle calculations that span multiple years. The functions will account for the total number of days, including leap years, to provide an accurate month count.

What happens if the start or end date falls on a holiday or weekend?

Excel’s date functions do not account for holidays or weekends unless specifically programmed to do so. They treat all days uniformly, regardless of whether they are workdays or not.

Is there a way to calculate months between dates excluding weekends?

To exclude weekends, you would need to use a combination of functions and possibly create a custom formula or use Excel’s Analysis ToolPak to access additional date and time functions.

Can DATEDIF calculate the difference in months and years at the same time?

To calculate the difference in both months and years, you would need to use DATEDIF twice—once for years and once for the remaining months—or create a more complex formula that combines multiple functions.


Calculating the number of months between dates in Excel is a versatile skill that can be applied to a wide range of scenarios. Whether you’re tracking project deadlines, analyzing financial periods, or managing subscription services, Excel’s date functions provide the precision and flexibility needed to get the job done. By mastering these functions and understanding how to combine them for complex calculations, you can unlock new levels of efficiency and insight in your data analysis tasks.


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