In this article, we will learn how to use Excel formulas to return the last date of a given month based on a date value. This can be useful for various purposes, such as calculating due dates, expiration dates, or monthly reports. We will cover the basic theory behind the formulas, the procedures to apply them, and some examples with real data. We will also explore some alternative formulas and approaches.

To return the last date of a given month in Excel, we need to use a function that can adjust the date value based on the number of months. One such function is the EOMONTH function, which stands for End Of Month. The EOMONTH function takes two arguments: a start date and a number of months. It returns the last day of the month that is the specified number of months before or after the start date. For example, if the start date is January 15, 2023, and the number of months is 0, the EOMONTH function will return January 31, 2023, which is the last day of the same month. If the number of months is 1, the EOMONTH function will return February 28, 2023, which is the last day of the next month. If the number of months is -1, the EOMONTH function will return December 31, 2022, which is the last day of the previous month.

Another function that can help us return the last date of a given month is the DATE function, which creates a valid date from individual year, month, and day components. The DATE function takes three arguments: a year, a month, and a day. It returns a date value that corresponds to the specified components. For example, if the year is 2023, the month is 1, and the day is 15, the DATE function will return January 15, 2023. However, the DATE function has a special feature that allows us to use zero or negative values for the day component. When we use zero as the day argument, the DATE function will roll back one day to the last day of the previous month. For example, if the year is 2023, the month is 2, and the day is 0, the DATE function will return January 31, 2023, which is the last day of the previous month. Similarly, if the year is 2023, the month is 1, and the day is -1, the DATE function will return December 31, 2022, which is the last day of the previous year.

Procedures

To use the EOMONTH function to return the last date of a given month, we need to follow these steps:

• Select a cell where we want to enter the formula.
• Type =EOMONTH( and select or type the cell reference that contains the start date.
• Type a comma and enter the number of months that we want to add or subtract from the start date. Use zero for the same month, positive values for future months, and negative values for past months.
• Type a closing parenthesis and press Enter.

To use the DATE function to return the last date of a given month, we need to follow these steps:

• Select a cell where we want to enter the formula.
• Type =DATE( and select or type the cell reference that contains the year component of the date.
• Type a comma and select or type the cell reference that contains the month component of the date. Add 1 to the month value to get the next month.
• Type a comma and enter zero as the day component to get the last day of the previous month.
• Type a closing parenthesis and press Enter.

Examples

Let’s see some examples of how to use the EOMONTH and DATE functions to return the last date of a given month in Excel. Suppose we have the following table of dates in column A:

We want to use the EOMONTH function to return the last date of the same month, the next month, and the previous month for each date in column A. We can enter the following formulas in columns B, C, and D, respectively:

The results will look like this:

We can see that the EOMONTH function returns the correct last date of the month for each case.