How to Calculate Your Own Intrinsic Stock Value

Here's a question most investors never seriously ask: What is this stock actually worth?

Not what it's trading for today. Not what it was worth last year or what analysts think it'll be worth next year. What it's intrinsically worth — based on the cash it generates, the earnings it produces, and the reasonable expectation of how that will grow.

This is the foundation of value investing, and it's more accessible than you might think. Benjamin Graham — Warren Buffett's mentor and the father of value investing — developed a formula anyone can use as a starting point.

Let's walk through it.

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The Core Idea: Price Versus Value

Before we get to the math, the concept matters.

The stock market assigns a price to every publicly traded company every second of every trading day. But price and value are not the same thing.

Price is what the market is willing to pay right now, driven by sentiment, momentum, fear, greed, news cycles, and countless other factors.

Value is a more stable number — what the business is actually worth based on its earnings power and growth prospects. It changes, but slowly, as fundamental business performance evolves.

When price is significantly below value, you potentially have a buying opportunity. When price is significantly above value, you're paying a premium that may or may not be justified. When they're roughly equal, there's no particular edge either way.

Graham's formula attempts to estimate value so you can compare it to price.

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Benjamin Graham's Intrinsic Value Formula

In his 1962 edition of The Intelligent Investor, Graham proposed a simple formula for estimating intrinsic value:

Intrinsic Value = EPS × (8.5 + 2g)

Where:

• EPS = Earnings Per Share (trailing twelve months)
• 8.5 = Graham's assumed P/E ratio for a no-growth company
• g = Expected annual earnings growth rate over the next 7–10 years (expressed as a percentage, not a decimal)

For example:

• A company earning $5.00 per share with an expected growth rate of 10% per year
• Intrinsic Value = $5.00 × (8.5 + 2 × 10) = $5.00 × 28.5 = $142.50

If the stock is trading at $100, it appears undervalued relative to Graham's estimate. If it's trading at $200, it looks overvalued.

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The Updated Graham Formula (With Bond Yield Adjustment)

Graham later updated this formula to account for the prevailing interest rate environment. Higher interest rates make future earnings worth less (a core concept in valuation), so the formula should adjust accordingly.

The revised version:

Intrinsic Value = [EPS × (8.5 + 2g) × 4.4] / Y

Where:

• 4.4 = Graham's baseline long-term AAA corporate bond yield at the time (the "risk-free" reference rate he used)
• Y = Current yield on 20-year AAA corporate bonds

This adjustment makes the formula more sensitive to the rate environment. When interest rates are low, intrinsic value estimates rise (future earnings are worth more in present value terms). When rates are high, estimates fall.

This is not just a formula quirk — it reflects genuine economic reality. A dollar of future earnings is worth more when you can't earn much on safe bonds, and worth less when high-quality bonds are offering 6–7% returns.

To find the current AAA corporate bond yield, you can look up the Federal Reserve's H.15 release or use a financial data site like FRED (Federal Reserve Economic Data), which is free.

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Finding the Key Inputs

The formula only works as well as the numbers you feed it. Here's how to find each input:

Earnings Per Share (EPS)

Use trailing twelve months (TTM) EPS, which represents the most recent four quarters of reported earnings. You can find this on any financial data site — Yahoo Finance, Macrotrends, and EDGAR (SEC filings) are all free sources.

A few things to watch:

• One-time items: Large one-time charges or gains can distort EPS in a given year. Look at normalized or adjusted EPS if a single quarter seems wildly out of the ordinary.
• Loss-making companies: The formula doesn't work for companies with negative earnings. It's a tool for established, profitable businesses.

Growth Rate (g)

This is the hardest input, because it requires forecasting — and forecasts are uncertain.

Common approaches:

• Historical growth rate: Look at EPS growth over the past 5–10 years. A company growing earnings at 12% annually for a decade is at least consistent.
• Analyst consensus: Financial data sites often publish the consensus EPS growth estimate from Wall Street analysts covering the stock.
• Conservative estimate: Graham himself suggested being conservative. For most companies, assuming a growth rate above 15% for a 10-year period is optimistic. Gravity exists in business.

Be especially skeptical of high growth assumptions for mature businesses. A company that's been growing earnings at 5–7% for years is unlikely to suddenly accelerate to 20%.

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The Margin of Safety

This concept is arguably more important than the formula itself.

Even if you calculate an intrinsic value of $142 per share, you shouldn't pay $142. Because your inputs might be wrong — growth might be slower than expected, one-time events might hit earnings, interest rates might rise.

Graham's principle of margin of safety says: only buy when the price is significantly below your estimated intrinsic value. He often suggested requiring a 33–50% discount.

If your intrinsic value estimate is $142, a 33% margin of safety means you'd look to buy at $95 or below. A 50% margin of safety means waiting for $71.

This cushion serves two purposes:

1. Error buffer: If your estimate is wrong (and it will sometimes be), you have room to still not lose money.
2. Return amplifier: Buying a $142 asset for $95 creates immediate upside when (if) the market price converges toward value.

The margin of safety is not a sign of pessimism. It's intellectual humility about the limits of forecasting.

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Real Limitations You Need to Understand

Graham's formula is a starting point, not a verdict. Here are the most important limitations to keep in mind:

1. It's backward-looking (mostly) EPS is based on past earnings. Past performance doesn't guarantee future results. Businesses change — competitors emerge, industries shift, management makes good and bad decisions.

2. Growth rates are guesses The "g" input requires you to predict how a company will grow over 7–10 years. Nobody can do this reliably. Even professional analysts with enormous research resources are frequently wrong. Be humble with your growth assumptions.

3. It ignores balance sheet quality The formula uses only earnings and growth. It doesn't account for how much debt a company carries, how much cash it has, or the quality of its assets. A highly leveraged company might look cheap on this formula but carry significant hidden risk.

4. It doesn't work for all business types The Graham formula works reasonably well for stable, profitable companies with predictable earnings. It doesn't work for:

• Money-losing companies (no positive EPS)
• Financial companies (banks, insurance) where earnings are structured differently
• Early-stage growth companies where current earnings are minimal but future potential is enormous
• Commodity businesses where earnings are highly cyclical

5. It was designed for a different era Graham developed this formula in the mid-20th century. The business environment has changed — more asset-light businesses, more intangible value, different competitive dynamics. Use it as a lens, not a ruler.

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How to Actually Use This

Here's a practical workflow:

1. Identify profitable companies you understand. You need to know something about the business to make a reasonable growth assumption.
2. Pull TTM EPS from a free source (Yahoo Finance, Macrotrends).
3. Make a conservative growth assumption — look at historical growth and lean toward the lower end.
4. Look up the current AAA corporate bond yield for the updated formula.
5. Calculate intrinsic value using the formula above.
6. Apply your margin of safety (33–50%).
7. Compare to current market price. Is there a meaningful gap? Or does the stock look fairly priced or expensive?

This process won't tell you exactly what to buy. But it will help you develop intuition about whether the market is pricing things reasonably or irrationally — and that intuition compounds over time.

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The Bottom Line

You don't need to be a Wall Street analyst to think critically about what a stock is worth. Graham's formula gives you a structured way to translate business fundamentals — earnings and growth — into a rough estimate of value.

The formula has real limitations. No formula can predict the future. But the discipline of asking "what am I actually paying for this earnings power?" separates patient, analytical investors from speculators chasing momentum.

Use it as one tool in a broader toolkit. Combine it with balance sheet analysis, competitive moat assessment, and a healthy dose of humility about the limits of prediction.

Value is uncertain. But having an estimate — even an imperfect one — beats investing blind.

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