Graham Number Guide for Value Investors

The Graham Number is a valuation formula created by Benjamin Graham to help investors estimate a fair maximum price for a stock. It combines two key financial metrics: earnings per share and book value per share.

In simple terms, the Graham Number asks one key question:

Is this stock trading at a reasonable price based on what the company earns and what it owns？

The formula was designed for defensive investors—those who prefer stable, established companies rather than speculative or high-risk stocks. Graham believed investors should avoid overpaying, even for high-quality businesses. His philosophy centered on the concept of a margin of safety, which means buying a stock below its estimated intrinsic value.

A stock trading below its Graham Number may be considered potentially undervalued. A stock trading significantly above it may be priced too aggressively, at least according to Grahams conservative framework.

Why the Graham Number Still Matters

The stock market has changed dramatically since Benjamin Grahams time. Companies today are often more global, technology-driven, and dependent on intangible assets such as software, patents, brands, and data.

Even so, the Graham Number remains relevant because the principle behind it has not changed: investors should avoid overpaying.

The Graham Number provides value investors with a quick screening tool to identify companies that may warrant further research. It is particularly useful for investors seeking profitable businesses with tangible assets and reasonable valuations.

It also promotes a disciplined investment mindset. Rather than chasing market hype, investors are encouraged to focus on earnings, equity, and valuation. Even as an initial screening tool, that makes the Graham Number valuable.

Graham Number Formula

The Graham Number formula is:

Graham Number = √ (22.5 × Earnings Per Share × Book Value Per Share)

The result represents an estimated maximum fair price per share based on Grahams value investing framework.

The number 22.5 comes from Grahams preferred valuation limits. He believed a reasonably priced stock should generally trade below a price-to-earnings ratio of 15 and a price-to-book ratio of 1.5.

When multiplied together, these two limits equal 22.5. This allows the Graham Number to combine both profitability and asset value into a single valuation measure.

Key Takeaway: The Graham Number is designed as a conservative valuation tool. It works best as an initial screening method rather than a complete valuation model.

Graham Number Example

Imagine a company reports the following financial data:

• Earnings per share (EPS): $3

• Book value per share (BVPS): $20

Using the Graham Number formula:

Graham Number = √ (22.5 × 3 × 20)

This gives:

Graham Number = √1,350 ≈ $36.74

Based on this calculation, Grahams framework suggests that a defensive investor should not pay more than approximately $36.74 per share.

If the stock is currently trading at $28, it may appear undervalued and warrant further analysis. If it is trading at $50, it may be expensive based on this valuation method.

Finding EPS and Book Value

To calculate the Graham Number, investors need two inputs.

Earnings per share (EPS) measures how much profit a company generates for each outstanding share. It is typically reported on the income statement and widely available through financial data providers.

Book value per share (BVPS) represents the companys net asset value divided by the number of outstanding shares.

Most stock research platforms already provide both figures, so investors rarely need to calculate them manually. However, understanding where these numbers originate is important, as accounting adjustments, one-time gains, or unusual losses can influence the results.

Understanding the Graham Number

The Graham Number reflects Benjamin Grahams conservative approach to investing. He encouraged investors to buy companies at sensible prices rather than emotional ones. By combining earnings per share with book value per share, the formula evaluates two important aspects of a business.

Earnings per share measures profitability, while book value per share reflects the companys asset base. Together, they help investors avoid companies that appear inexpensive based solely on earnings but have weak balance sheets, as well as companies with substantial assets but poor profitability.

The square root in the formula converts the combined value into an estimated share price that investors can compare directly with the current market price.