Graham Number Calculator: How to Use Benjamin Graham's Formula

April 6, 2026 · Stock Analysis · 8 min read

Benjamin Graham, the father of value investing, believed that the most important concept in investing was the margin of safety. He developed a formula to calculate a stock's intrinsic value in a single number: the Graham Number.

The Graham Number is simple enough that you can calculate it with a calculator. But its implications are profound — it answers one fundamental question: what's the maximum price I should pay for a stock to have a real margin of safety?

What Is the Graham Number?

The Graham Number is calculated using a deceptively simple formula:

Graham Number = v(22.5 — EPS — Book Value Per Share)

Breaking it down:

The result is a single dollar value. If the stock is trading below this number, it theoretically has a margin of safety. If it's trading above, it's overpriced by Graham's standard.

Step-by-Step Calculation with Real Numbers

Let's work through a real example. Suppose a company has:

The calculation:

  1. Multiply EPS — BVPS: 5.50 × 22.00 = 121
  2. Multiply by 22.5: 121 × 22.5 = 2,722.5
  3. Take the square root: v2,722.5 = 52.18

The Graham Number is $52.18.

If the stock is trading at $40, it has a margin of safety of roughly 23% ($52.18 - $40 = $12.18 / $52.18 = 23%).

If the stock is trading at $65, it's overpriced by about 25% according to Graham's method.

Why This Formula Works (And Why It Doesn't)

Why It Works

Graham's formula is elegant because it combines two different ways of looking at value:

  1. Earnings power — the P/E component (via EPS and the 22.5 constant)
  2. Asset value — the book value component (BVPS)

A healthy company generates earnings, but it's also built on real assets. The formula requires both to be reasonable. This prevents you from paying too much for either speculative earnings or cheap asset values.

The historical data Graham used showed that stocks trading below this number historically had better long-term returns. That's still true today — but with caveats.

Why It Doesn't Work (Or At Least, Why It's Limited)

The Graham Number has significant blind spots:

1. It ignores growth entirely. A fast-growing company might have low current earnings but enormous future cash flows. The Graham Number penalises growth stocks by definition. A tech company with $2 EPS but 40% annual growth might have a Graham Number of $30, but its true fair value could be much higher.

2. Book value is arbitrary. For asset-light companies (software, services), book value is nearly meaningless. For manufacturing or real estate companies, it's more relevant. The formula treats them the same.

3. It doesn't account for competitive advantages. A company with a strong brand or network effect should trade at a premium to a commodity competitor with the same earnings and assets. The Graham Number ignores this.

4. The 22.5 constant is historical. Graham developed this in the mid-20th century when market conditions, interest rates, and capital structures were different. Is 22.5 still the right multiplier? Probably not — it's more of a guideline now than a law.

How to Interpret Graham Number Results

Undervalued by Graham's Standard (Price < Graham Number)

If a stock trades below its Graham Number, it meets Graham's safety criteria. But this doesn't mean the stock is a good investment.

You still need to verify:

Overvalued by Graham's Standard (Price > Graham Number)

Many great companies trade above their Graham Number. Apple, Microsoft, Coca-Cola — all trade at multiples Graham would have rejected.

This doesn't mean they're bad investments. It means:

Margin of Safety Application

Graham's core principle was that margin of safety is the difference between your estimate of value and what you pay. The Graham Number is one way to estimate that value — but it's not the only way.

When you calculate the Graham Number, you're asking: "By this formula's standard, how much cushion do I have?"

A 20%+ margin of safety (stock trading 20% or more below Graham Number) gives you real protection against:

A margin of safety under 10% means there's limited room for error. And if the stock trades above Graham Number, you have negative margin of safety by this metric — the stock would have to fall for the formula to approve.

Variations and Modifications to Graham's Formula

Over the decades, investors have modified Graham's formula to adapt to different market conditions and company types.

Graham Number for Growth Stocks: Some analysts replace 22.5 with a higher constant (like 30–35) to account for growth. This rewards fast-growing companies while still maintaining a safety margin.

Graham Number for Mature Companies: Value investors often use a lower multiplier (15–20) for mature, slow-growth businesses, being more conservative on what they'll pay.

Book Value Adjustments: Some investors adjust BVPS for intangible items — reducing it for goodwill or inflated assets, increasing it for hidden value like valuable real estate. This requires deeper balance sheet analysis but improves accuracy.

Earnings Quality Adjustments: Graham's formula uses reported EPS, but sophisticated analysts normalize for one-time items, accounting changes, or stock-based compensation. Using "normalized" EPS instead of trailing twelve-month EPS can give a clearer picture.

The key insight: Graham's formula is a framework, not a law. You can adapt it to your investment philosophy.

How to Use Graham Number in Real Screening

In practice, here's how value investors combine Graham Number with other signals:

  1. Screen for stocks trading below their Graham Number — This gives you the universe of candidates
  2. Layer in additional quality filters — Earnings quality, cash flow generation, debt levels
  3. Calculate margin of safety percentages — Rank candidates by how far below Graham Number they trade
  4. Compare to other valuation methods — If Graham Number, DCF, and P/E all agree the stock is cheap, conviction is higher
  5. Investigate the "why" — Why is the market pricing this stock below Graham's estimate? Is it temporary weakness or a real problem?

A stock trading 40% below Graham Number is interesting. A stock trading 40% below Graham Number and 35% below DCF fair value while showing improving earnings quality is compelling.

How Equity Rank Goes Beyond Graham

Graham's Number is one lens. Equity Rank uses eight different valuation methods to build a consensus view of fair value:

  1. Price-to-Earnings (P/E) — similar to Graham's earnings component, but context-adjusted for sector and growth
  2. Discounted Cash Flow (DCF) — estimates future cash flows in today's dollars, capturing growth
  3. Price-to-Book (P/B) — Graham's asset value approach
  4. PEG Ratio — P/E adjusted for growth, fixing one of Graham's blind spots
  5. EV/EBITDA — useful for capital-intensive companies
  6. Price-to-Sales — revenue-based valuation, immune to accounting manipulation
  7. Free Cash Flow Yield — the cash a company actually generates relative to market cap
  8. Dividend-adjusted valuation — for income-focused stocks

The platform also applies the SAVE score, which adds market sentiment and quality factors. The result is a fair value estimate that captures what Graham was trying to do — establish a conservative, safety-first valuation — but without the single-formula limitations.

When you're screening for opportunities, using multiple methods like Equity Rank does is more powerful than relying on Graham Number alone. But understanding Graham's formula teaches you the principle behind all of them: value is what you get, price is what you pay, and the gap between them is safety.

Screen for undervalued stocks at Equity Rank

For informational purposes only. Not financial advice. Equity Rank is not a registered investment adviser. The Graham Number is one valuation framework among many. Always conduct your own research and consult a financial professional before making investment decisions.