Graham Number Explained: Formula, Calculator, and How to Use It

The Graham Number is one of the most widely searched valuation formulas in retail investing — and for good reason. It distills two of Benjamin Graham's most important valuation principles into a single calculation that any investor can run in seconds.

But the Graham Number is also one of the most misused formulas in stock analysis. Investors treat it as a standalone verdict when it is actually a starting point: a quick screen for whether a stock is worth investigating further.

This guide explains what the Graham Number is, exactly how to calculate it with a worked example, why the constant 22.5 is embedded in the formula, where the formula breaks down, and how to use it alongside other tools to make more complete valuation judgments.

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Who Was Benjamin Graham?

Benjamin Graham was an economist, professor, and professional investor widely credited as the father of value investing. His two foundational books — Security Analysis (1934, co-authored with David Dodd) and The Intelligent Investor (1949) — remain among the most influential texts in finance.

Graham spent decades teaching at Columbia Business School, where one of his most famous students was a young Warren Buffett. Buffett has called The Intelligent Investor "by far the best book about investing ever written."

Graham's core insight was that stocks have an intrinsic value independent of market price, and that rational investors can profit by purchasing shares at a significant discount to that intrinsic value — a concept he called the margin of safety. The Graham Number is a practical expression of that principle applied to two fundamental accounting inputs: earnings and book value.

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The Graham Number Formula

The Graham Number is calculated as follows:

Graham Number = square root of (22.5 x EPS x BVPS)

Where:

• EPS = earnings per share (trailing twelve months, from net income attributable to common shareholders)
• BVPS = book value per share (total shareholders' equity divided by shares outstanding)
• 22.5 = a constant derived from Graham's valuation thresholds (explained below)
• square root = applied to the full product

The result is a per-share dollar figure. If the Graham Number is higher than the current market price, the stock may warrant further investigation as a potentially undervalued candidate. If the current price significantly exceeds the Graham Number, the stock is priced above what Graham's framework considers reasonable for a defensive investor.

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Why 22.5? The Logic Behind the Constant

The constant 22.5 is not arbitrary. Graham established two separate valuation thresholds:

• Maximum P/E ratio of 15 — Graham believed that a defensive investor should not pay more than 15 times earnings for any stock
• Maximum P/B ratio of 1.5 — Graham believed that a defensive investor should not pay more than 1.5 times book value per share

When you multiply these two limits together: 15 x 1.5 = 22.5

So the Graham Number is effectively asking: what is the maximum price that simultaneously respects both a 15 P/E ceiling and a 1.5 P/B ceiling? The square root converts the product of (P/E limit x earnings) and (P/B limit x book value) back into a single price figure.

This is elegant because it penalizes stocks that are expensive on both dimensions at once. A stock trading at 14x earnings but 2x book value would exceed the Graham Number even though it satisfies one of the individual thresholds.

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Worked Example: Calculating the Graham Number

Suppose a company reports the following:

• Trailing twelve-month EPS: 4.20
• Book value per share: 28.50

Step 1: Multiply EPS by BVPS.

4.20 x 28.50 = 119.70

Step 2: Multiply by 22.5.

119.70 x 22.5 = 2,693.25

Step 3: Take the square root.

square root of 2,693.25 = 51.90

The Graham Number for this stock is approximately 51.90 per share.

If this stock is currently trading at 38.00, it sits well below the Graham Number, which flags it as a candidate for deeper fundamental research. If it is trading at 72.00, it is priced nearly 40% above Graham's maximum threshold, which would place it outside his criteria for a defensive purchase — at that price, the margin of safety has been eliminated.

Want to skip the math? Equity Rank calculates the Graham Number automatically on every stock page alongside seven other valuation methods, so you can compare estimates instantly at equity-rank.com.

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Where to Find EPS and Book Value Per Share

Both inputs are available in a company's financial statements:

EPS (Earnings Per Share)

• Found on the income statement and in the earnings per share section of any financial data provider
• Use diluted EPS to account for all potential share dilution from options, warrants, and convertibles
• Use trailing twelve months (TTM) rather than a single fiscal year when possible — this captures the most recent four quarters of earnings
• If EPS is negative (the company is losing money), the Graham Number cannot be calculated — the formula produces an imaginary number

Book Value Per Share (BVPS)

• Found on the balance sheet as total shareholders' equity
• Divide total shareholders' equity by shares outstanding
• Exclude preferred equity from the numerator if you want the figure attributable to common shareholders
• If book value is negative (liabilities exceed assets), the Graham Number again cannot be calculated and the formula breaks down

Both inputs are adjusted and pre-loaded inside Equity Rank's stock analysis pages, so you do not need to pull them manually from financial statements.

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Limitations of the Graham Number

The Graham Number is a powerful quick screen, but it has real weaknesses that every user of the formula should understand before acting on the output.

It was designed for defensive, asset-heavy businesses

Graham wrote The Intelligent Investor in an era when most profitable businesses required substantial physical assets — factories, inventory, equipment. The formula's reliance on book value made sense when book value closely approximated the replacement cost of a business.

Today, the most valuable companies in the world are asset-light: software firms, platform businesses, brands. A company like a major software provider might have enormous earnings power and almost no tangible book value. For these companies, BVPS is nearly zero, the Graham Number collapses to near zero as well, and the formula provides no useful output.

It ignores growth entirely

Graham's framework was explicitly designed for defensive investors — those prioritizing capital preservation over growth. He was not trying to value high-growth businesses, and the formula reflects that. A company growing earnings at 25% per year might be fairly valued at 30x or 40x earnings, well above Graham's 15x ceiling. The Graham Number would call it wildly overpriced. It is not overpriced — it is growing, and the formula is not equipped to value that.

For growth stocks, tools like the PEG ratio, DCF analysis, or EV/EBITDA relative to growth rate are better suited.

It uses historical, backward-looking inputs

EPS and book value are historical figures. They tell you what the company earned and owned as of the last reporting period. They say nothing about what the company will earn going forward. If earnings are about to collapse — due to a product cycle ending, a competitive threat, or a one-time write-down — the Graham Number based on trailing data will produce an overly optimistic figure.

Goodwill and intangibles can inflate book value artificially

Companies that have made acquisitions often carry large amounts of goodwill on the balance sheet. This can inflate BVPS significantly. If that goodwill is impaired (the acquired business underperforms), book value will drop and the Graham Number will reset downward. Some analysts strip goodwill and intangibles from book value before calculating BVPS — producing a "tangible book value per share" figure — which gives a more conservative and arguably more honest input.

It is a price ceiling, not an intrinsic value estimate

The Graham Number does not claim to tell you what a stock is worth. It tells you the maximum price Graham believed a defensive investor should pay given two specific thresholds. A stock trading at exactly the Graham Number is not necessarily at fair value — it is at Graham's maximum acceptable price. Investors who want a genuine intrinsic value estimate need DCF analysis or a more complete multi-method valuation.

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What to Do If a Stock Is Below the Graham Number

A stock trading below its Graham Number is not a buy signal. It is a flag that the stock may be worth investigating further. Here is a rational process for what to do next.

Step 1: Verify the inputs are clean

Before relying on the result, confirm that trailing EPS is not distorted by one-time items (asset sales, legal settlements, tax benefits). A single extraordinary gain can make EPS look far higher than the business's normal earning power. Similarly, check book value for large goodwill balances or recent impairment charges.

Step 2: Check financial health

A low price relative to the Graham Number can indicate undervaluation, or it can indicate a business in distress. Check the debt-to-equity ratio and interest coverage. If the company carries excessive debt, the low stock price may be rational — equity holders are exposed to significant downside if the business cannot service its obligations.

Step 3: Assess earnings trend

Is the company earning consistently? Or did it report an unusually strong year that inflated EPS? Look at EPS over three to five years to gauge whether the current figure is representative. A single strong year followed by declining earnings is a warning sign, not a green light.

Step 4: Apply a margin of safety

Graham himself advised not buying at the Graham Number ceiling — he advocated buying at a meaningful discount to any valuation estimate to provide a buffer for error. Many practitioners apply a 20% to 30% discount to the Graham Number as their actual entry threshold. This means a stock with a Graham Number of 50.00 would need to trade at 35.00 to 40.00 before meeting their criteria.

Step 5: Cross-check with other valuation methods

The Graham Number is one data point, not a verdict. Cross-check it against DCF intrinsic value, EV/EBITDA multiples, the PEG ratio, and analyst consensus. If multiple methods converge on the same conclusion — that a stock may be undervalued — the case for deeper research strengthens.

Equity Rank runs eight valuation methods simultaneously on every stock and synthesizes them into a single SAVE score, which represents the proportion of methods indicating the stock may correspond to potential undervaluation. Rather than relying on the Graham Number alone, you can see how it compares to seven other approaches in one view at equity-rank.com.

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Graham Number vs. Other Valuation Methods

It helps to understand where the Graham Number fits in the broader toolkit.

Method	What It Measures	Best For
Graham Number	Max price at 15x P/E and 1.5x P/B	Defensive screening of value stocks
DCF	Intrinsic value from projected cash flows	Any cash-generating business
P/E ratio	Earnings multiple	Profitable companies across most sectors
PEG ratio	P/E adjusted for growth	Growth-oriented companies
EV/EBITDA	Enterprise value relative to operating earnings	Capital-structure comparisons
Price-to-Book	Asset-based valuation	Banks, insurers, industrial firms

No single method dominates all situations. The Graham Number is fastest and simplest — useful as a first filter — but it should hand off to deeper analysis rather than serving as a final conclusion.

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A Note on Graham's Own Evolution

It is worth noting that Benjamin Graham himself softened his strict formula-based approach near the end of his career. In later interviews, he acknowledged that simpler screening approaches — looking for stocks trading below a certain multiple of net tangible asset value or below a modest earnings multiple — could identify undervalued stocks without the precision the formula implies.

The spirit of his work was always the same: pay less than a business is worth, maintain a margin of safety, and let time do the rest. The specific formula is a tool for implementing that spirit, not a law to follow mechanically.

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Summary: What the Graham Number Is and Is Not

What it is:

• A quick price ceiling estimate grounded in two conservative valuation thresholds (15x earnings, 1.5x book)
• An effective first-pass screen for potentially undervalued, asset-heavy, profitable businesses
• A practical expression of Graham's defensive investor framework

What it is not:

• An intrinsic value estimate
• A trading signal
• Applicable to growth stocks, asset-light businesses, or companies with negative earnings or book value
• A substitute for full fundamental analysis

Used correctly — as a screen to flag candidates for deeper research, not as a standalone verdict — the Graham Number remains one of the most useful formulas in retail investing, even 70 years after Graham first published it.

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Calculate the Graham Number Instantly

Equity Rank calculates the Graham Number automatically on every stock analysis page, alongside DCF, P/E, P/B, EV/EBITDA, PEG, and three additional valuation methods. Each method is benchmarked, scored, and synthesized into the SAVE score — a composite indicator of how many valuation frameworks may suggest undervaluation for any given stock.

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Directional accuracy figures referenced elsewhere on this site are based on simulation, not live trading results. Nothing on Equity Rank constitutes investment advice. All valuation outputs are model estimates based on historical accounting data and user-selected assumptions.

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Frequently Asked Questions

Is the Graham Number still relevant in 2026?

Yes — for the right types of companies. For profitable, asset-heavy businesses in sectors like industrials, financials, consumer staples, and utilities, the formula remains a useful quick screen. For software, biotech, and high-growth companies, the formula does not apply and should not be used.

What does it mean if a stock is below its Graham Number?

It means the stock's current price is below Benjamin Graham's maximum price threshold for a defensive investor. It does not guarantee undervaluation — it flags the stock as a candidate for deeper analysis. The next step is checking financial health, earnings consistency, and cross-referencing other valuation methods.

Should I use diluted or basic EPS in the Graham Number?

Diluted EPS. Diluted EPS accounts for all potential share issuance (options, convertibles, warrants) and gives you the most conservative earnings-per-share figure, which is appropriate for a formula designed around conservative valuation.

Can I use forward EPS instead of trailing EPS?

Some analysts substitute consensus forward EPS estimates to produce a forward-looking Graham Number. This can be useful for businesses with rapidly changing earnings, but it introduces forecast risk. Graham's framework was designed around known historical data, not estimates. If you use forward EPS, treat the result as more uncertain and apply a wider margin of safety.

What is a good Graham Number margin of safety?

Graham himself advocated buying at a substantial discount to intrinsic value — often cited as 33% or more. Many practitioners apply a 20% to 30% discount to the Graham Number ceiling before considering a stock for their watchlist. At that level, if your inputs are slightly wrong, you still have buffer before you've overpaid.