CAPE Ratio Explained: What It Is and How to Calculate It | TIOmarkets

BY TIO Staff

|June 12, 2024

The CAPE Ratio, or the Cyclically Adjusted Price-to-Earnings ratio, stands as a pivotal metric in the realm of investment analysis. This guide aims to demystify the CAPE Ratio, offering a comprehensive understanding of its significance and the methodology behind its calculation.

Understanding the CAPE Ratio

The CAPE Ratio extends beyond the conventional P/E ratio by incorporating earnings data from over a decade to smooth out fluctuations caused by economic cycles. This long-term perspective provides a more stable benchmark for assessing a stock's valuation.

Developed by Nobel Laureate Robert Shiller, the CAPE Ratio is often used to gauge whether a stock is undervalued, fairly valued, or overvalued compared to historical standards. It's a tool that can aid investors in making informed decisions.

Why the CAPE Ratio Matters

The CAPE Ratio's significance lies in its ability to offer a long-term view of a stock's profitability and potential for growth. By considering a decade's worth of earnings, the CAPE Ratio smooths out short-term volatilities, providing a clearer picture of underlying value.

This metric is particularly useful in identifying market bubbles or periods of undervaluation, making it a valuable resource for strategic investment planning.

Comparing CAPE Ratio with Standard P/E Ratio

While the standard P/E ratio considers only the latest year's earnings, the CAPE Ratio takes into account 10 years of earnings, adjusted for inflation. This adjustment for economic cycles and inflation makes the CAPE Ratio a more reliable measure of a stock's long-term value.

The standard P/E ratio can be misleading during periods of economic volatility, as it may not accurately reflect a company's profitability over time. The CAPE Ratio addresses this limitation, offering a more nuanced view of valuation.

How to Calculate the CAPE Ratio

Calculating the CAPE Ratio involves a few steps but is straightforward once the process is understood. It requires historical earnings data, inflation adjustments, and the current price of the stock.

Gathering the Necessary Data

The first step in calculating the CAPE Ratio is to compile the last 10 years of a company's earnings. This data must then be adjusted for inflation to ensure that all earnings are expressed in today's dollars, providing a consistent basis for comparison.

Calculating the Average Inflation-Adjusted Earnings

Once the earnings have been adjusted for inflation, the next step is to calculate the average of these inflation-adjusted earnings over the 10-year period. This average represents a stable measure of the company's profitability, free from short-term economic fluctuations.

Finalizing the CAPE Ratio

The final step involves dividing the current price of the stock by the 10-year average of inflation-adjusted earnings. The resulting figure is the CAPE Ratio, which can then be compared against historical averages to assess valuation.

Interpreting the CAPE Ratio

Understanding how to interpret the CAPE Ratio is crucial for applying it effectively in investment analysis. A higher CAPE Ratio suggests that a stock may be overvalued, while a lower ratio indicates potential undervaluation.

Historical Context

It's important to compare a stock's CAPE Ratio not just in isolation but against historical averages for the stock itself, its sector, and the broader market. This context can provide insights into relative valuation and potential future performance.

Risks and Limitations

While the CAPE Ratio is a powerful tool, it's not without its limitations. The ratio may not be as effective in industries with rapid innovation or significant changes in business models. Additionally, it's essential to consider other factors, such as market conditions and future growth prospects, in any investment decision.

The CAPE Ratio has gained popularity among investors and analysts due to its ability to provide a more comprehensive view of a company's valuation. By smoothing out short-term fluctuations, the CAPE Ratio offers a clearer picture of a stock's true worth over an extended period.

Application in Market Analysis

Investors often use the CAPE Ratio to assess broader market conditions, not just individual stock valuations. By calculating the CAPE Ratio for an entire market index, such as the S&P 500, analysts can gain insights into whether the market as a whole is overvalued or undervalued.

This macro-level analysis can help investors make strategic decisions regarding asset allocation and portfolio diversification, based on the overall valuation levels indicated by the CAPE Ratio.

One of the key advantages of the CAPE Ratio is its ability to provide a forward-looking perspective on stock valuations. By considering long-term earnings data, investors can better evaluate a company's growth potential and assess whether its current price accurately reflects its future earnings prospects.

Global Application

While the CAPE Ratio is commonly used in the United States, its principles can be applied globally to assess stock markets in other countries. By adjusting earnings for inflation and considering long-term averages, investors can compare valuations across different regions and make informed decisions on international investments.

However, it's important to recognize that economic and market dynamics vary between countries, so the interpretation of CAPE Ratios in a global context should consider local factors and conditions.


The CAPE Ratio offers a robust framework for evaluating stock valuations over the long term, smoothing out short-term economic and market volatilities. By understanding and applying the CAPE Ratio, investors can enhance their ability to identify undervalued or overvalued stocks, making more informed investment choices. However, like any analytical tool, it should be used in conjunction with a comprehensive analysis of market conditions, industry trends, and individual company prospects.

At TIOmarkets, we are committed to providing our clients with the tools and knowledge needed to navigate the complexities of the financial markets. Understanding the CAPE Ratio is just one aspect of building a successful investment strategy.

Start Applying the CAPE Ratio with TIOmarkets

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TIO Staff

Behind every blog post lies the combined experience of the people working at TIOmarkets. We are a team of dedicated industry professionals and financial markets enthusiasts committed to providing you with trading education and financial markets commentary. Our goal is to help empower you with the knowledge you need to trade in the markets effectively.

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