Calculation Issues

How to Calculate Average Monthly Rate of Change in Excel

Maira Mehtab Oct 9, 2026 869 views

Question details

The user needs to calculate the average percentage change between monthly totals across a given period.

How to Calculate Average Monthly Rate of Change in Excel

Product: Microsoft Excel
Device & OS: not provided
Scenario: Analyzing monthly data trends, such as call totals or sales, to find the average growth or decline rate.
Observed behavior: Requires a formula to compute the month-over-month percentage changes and average them into a single metric.

Before you start

Ensure your monthly data is arranged chronologically in a single row or column, without any blank cells or text values that could cause calculation errors.

Solution 1Recommended

Use a Single Formula for Average Monthly Change

Calculate the average rate of change directly using an all-in-one AVERAGE formula.

This method calculates the percentage change between each consecutive month and averages those changes in a single cell, avoiding the need for extra columns.

Select the Destination Cell

Click on the cell where you want the final average percentage to appear (for example, cell M1).

Enter the AVERAGE Formula

Assuming your monthly data spans from January to December in cells A1 through L1, type the following formula: =AVERAGE((B1-A1)/A1,(C1-B1)/B1,(D1-C1)/C1,(E1-D1)/D1,(F1-E1)/E1,(G1-F1)/F1,(H1-G1)/G1,(I1-H1)/H1,(J1-I1)/I1,(K1-J1)/J1,(L1-K1)/K1)

Format as Percentage

Press Enter to apply the formula. Then, go to the Home tab and click the '%' (Percentage Style) icon in the Number group to format the decimal output as a percentage.

Use a Single Formula for Average Monthly Change

Adjusting Cell References: If your data is located in a column instead of a row (e.g., A1:A12), adjust the formula to reference the rows accordingly, such as =AVERAGE((A2-A1)/A1, (A3-A2)/A2, ...).

Solution 2

Use a Helper Row for Step-by-Step Calculation

Calculate the individual month-to-month changes first, then average the results. This method is easier to maintain and troubleshoot.

Data Analysis Made Easy

Calculate Rates of Change Easily in WPS Spreadsheet

WPS Office offers a powerful Spreadsheet tool that fully supports all Excel formulas, including AVERAGE and percentage calculations, allowing you to analyze monthly trends seamlessly and for free.

1. Open Your Data: Launch WPS Spreadsheet and open the file containing your monthly totals.
2. Apply the Formula: Select a blank cell and input the month-over-month average formula just as you would in Excel.
3. Format the Result: Use the 'Percentage Style' button on the Home tab to display your results clearly as a percentage.

Fully compatible with Microsoft Excel formulas and .xlsx file formats.Rich formatting tools to easily display percentage changes and financial data.Lightweight and fast performance even with large datasets.

microsoft office alternative - wps office

Frequently Asked Questions

Why am I getting a #DIV/0! error in my rate of change formula?

This error occurs if one of your starting month values is zero or empty, as Excel cannot divide by zero. You can wrap your individual month calculations in an IFERROR function, like =IFERROR((B1-A1)/A1, 0), to handle blank or zero months gracefully.

Can I use the geometric mean instead of the average for growth rates?

Yes. For compounding financial growth rates over a specific period, the Compound Annual Growth Rate (CAGR) or geometric mean is often more accurate than a simple average. You can calculate this using the formula =(Ending Value/Beginning Value)^(1/Number of Periods)-1.

How do I highlight negative percentage changes automatically?

You can use Conditional Formatting. Select the cells containing your percentage changes, navigate to the Home tab, click Conditional Formatting > Highlight Cells Rules > Less Than. Enter 0 in the box, and choose a format like 'Light Red Fill with Dark Red Text'.

Excel & Data Problems