Intrinsic Value: How to Estimate What a Stock Is Really Worth

Intrinsic value is an estimate of what a business is genuinely worth, based on its assets, its earnings and the cash it can generate over time — independent of whatever price the market happens to be quoting today. It is a judgement, not a fact printed on a screen. The whole craft of value investing rests on the idea that you can estimate this underlying worth well enough to know when the price is a bargain and when it is not.

Price is what you pay; value is what you get

Price and value are not the same thing, and confusing them is the most expensive mistake an investor can make. Price is the number the market quotes second by second; it moves with news, sentiment, fear and greed. Value is the slower, steadier figure that reflects what the business actually produces. Over short periods the two can drift far apart — a great company can trade cheaply when the crowd is fearful, and a mediocre one can trade dearly when it is fashionable. Closing that gap deliberately is the heart of value investing; the formal definition lives in the intrinsic value glossary entry.

Because the market sets prices through the collective mood of millions of participants, those prices overshoot in both directions. Your edge as a long-term investor is not predicting the mood — it is having an independent estimate of value to measure the mood against. Without that anchor, you have nothing to tell you whether today's price is cheap or expensive; you are simply hoping the next buyer pays more than you did.

Three ways to estimate intrinsic value

There is no single formula that hands you the right answer, but there are three classic lenses, each suited to a different kind of business. Used together, they triangulate a range rather than pretending to a single number.

The first is asset-based valuation. You add up what the company owns — cash, inventory, property, equipment — and subtract what it owes, arriving at net asset value, often expressed per share as book value per share. This lens works best for asset-heavy or distressed businesses, where the balance sheet is the clearest guide to worth. It is weakest for asset-light companies whose value lives in brands, software or people that never appear on the balance sheet.

The second is an earnings-based rule of thumb, the best known being the Graham Number. It blends earnings power and asset value into one quick ceiling on what a defensive investor should pay, drawing on earnings per share and book value per share. It is fast and disciplined, but deliberately crude — a screen, not a verdict — and it suits stable, profitable companies far better than fast-growing or loss-making ones.

The third is a discounted cash flow, the most complete and most demanding method. You project the cash the business will generate for years ahead and discount each year back to today using a rate that reflects its risk. A DCF forces you to state your assumptions explicitly, which is its great virtue, but it is exquisitely sensitive to those assumptions — small changes in growth or the discount rate swing the answer wildly. You can experiment with the building blocks using the present value calculator and the WACC calculator.

A worked example: the Graham Number

The Graham Number gives the clearest quick illustration. Its formula is the square root of 22.5 × earnings per share × book value per share. The 22.5 is a constant — it comes from a price-to-earnings ceiling of 15 multiplied by a price-to-book ceiling of 1.5 — so the number marks roughly the most a defensive investor should pay.

Suppose a company earns $4.00 per share and has a book value of $30 per share. The Graham Number = √(22.5 × 4 × 30) = √2700 ≈ $52. If the stock trades below about $52, it passes this conservative test; if it trades at $80, the Graham Number says you are paying well above the level a cautious investor would accept. Notice that the result is one estimate from one lens — useful as a filter, not a final verdict on what the business is worth.

Why your estimate is a range, not a number

It is tempting to want intrinsic value as a single precise figure, but that precision is an illusion. Every method rests on assumptions about the future — how fast earnings grow, how durable the moat is, what discount rate fits the risk — and reasonable people will disagree on each. A DCF that says a stock is worth exactly $103.47 is fooling you with false precision; the honest output is a band, perhaps "$80 to $120," reflecting how the answer moves as your assumptions move.

This is why the three lenses are best used together. If asset value, the Graham Number and a conservative DCF all cluster around the same region, you can hold your estimate with more confidence. If they scatter widely, that disagreement is itself information: it tells you the business is hard to value, and that you should demand a larger discount before buying — or pass entirely. The goal is not a perfect number but a range you can defend, and an honest sense of how wide that range is.

How a margin of safety protects you

Because your estimate is a range and your assumptions can be wrong, you never buy at your estimate of value — you buy well below it. That deliberate discount is the margin of safety, and it is what turns a fragile forecast into a robust decision. If you estimate value at $100 and pay $70, a 30% margin of safety, then even a valuation that proves 20% too optimistic still leaves you having paid below the real worth. The wider your uncertainty, the wider the discount you should insist on; we cover the sizing in margin of safety explained and define the term in the glossary.

In short, intrinsic value is the anchor and the margin of safety is the rope: one tells you what a business is worth, the other protects you when your estimate is off. Estimate value with more than one lens, accept that the result is a range, and only act when the price sits comfortably below it. From here, the natural next steps are putting the idea to work — learning how to find undervalued stocks, starting from first principles at the investing for beginners hub, or running the numbers yourself in the tools. The quickest first test is the Graham Number.

Written by

Federico Romaldi

Co-Founder, Worthmap

Published: June 6, 2026

Federico is a co-founder of Worthmap, a wealth-intelligence platform built for serious investors. With a background in software engineering and a long-standing passion for value investing, he created Worthmap to bridge the gap between net-worth tracking and investment analysis.