What is the EOMONTH Function?

Before we jump into examples, let’s understand what EOMONTH does. Simply put, EOMONTH returns the last day of a month that is a specified number of months before or after a given start date. It’s perfect for scenarios like calculating due dates, subscription renewals, or financial periods.

Here’s the syntax:

=EOMONTH(start_date, months)

• Start_date: The date you want to base your calculation on.
• Months: The number of months to add (positive) or subtract (negative).

EOMONTH automatically adjusts for varying month lengths, even leap years.

Example 1 – Rent Payment Due Dates

Imagine you’re a landlord managing a property rented from October 5, 2024. The lease requires rent to be paid by the last day of every month. Let’s calculate the due dates for the next 3 months.

In cell C2, type =EOMONTH(A2, B2).

Press Enter. The result will be October 31, 2024—the last day of the starting month.

Drag the formula down to C3 and C4 to calculate November and December’s due dates.

If cells show numbers like 45205, right-click the cells > Format Cells > Choose Date > Select your preferred style (e.g., 31-Oct-2024)

EOMONTH ignores the original day (e.g., October 5) and focuses on the month’s end. This ensures consistency, even if the start date isn’t the 1st.

Example 2 – Subscription Renewal Reminders

Now, let’s track subscription renewals. Suppose a customer’s subscription expires on March 15, 2025, and you need to send reminders 2 months before the expiry. Here’s how to find the reminder date:

In cell C5, type =EOMONTH(A5, B5).

Press Enter. The result will be January 31, 2025.

Why January 31? EOMONTH subtracts 2 months from March 15, landing on January 15. But since EOMONTH always returns the month’s end, it adjusts to January 31.

Video: