Margin of Safety Calculator
Know your buffer before you buy
Enter the price and your value estimate
Free · No sign-up · Updates as you type$
What the share trades at today, e.g. 65.
$
What you think a share is really worth, e.g. 100.
Margin of Safety
35.0%
Strong Buy
In plain terms: you value the share at $100.00 and it trades at $65.00, so you would buy it for $35.00 less than you think it is worth. That gap is 35.0% of your estimate: your margin of safety, the cushion if the estimate is too high or the price falls.
Current Price
$65.00
Intrinsic Value
$100.00
What if your value estimate is off?
The intrinsic value is an estimate, and your margin depends entirely on it. Here is how the margin and the verdict shift if your estimate is too high or too low.
| Fair value | Margin of Safety | Verdict |
|---|---|---|
| $80.00 (-20%) | 18.8% | Buy |
| $90.00 (-10%) | 27.8% | Buy |
| $100.00 (yours) | 35.0% | Strong Buy |
| $110.00 (+10%) | 40.9% | Strong Buy |
| $120.00 (+20%) | 45.8% | Strong Buy |
What this means: At over 30%, this stock appears significantly underpriced relative to your estimate, a classic value investing entry point.
The reliability of this result depends entirely on the quality of your intrinsic value estimate. Use our Graham Number calculator or a DCF model to estimate intrinsic value.
This calculator applies the classic value investing formula pioneered by Benjamin Graham: Margin of Safety (%) = (Intrinsic Value − Current Price) ÷ Intrinsic Value × 100. A positive result means the stock is trading below your estimated fair value; a negative result means it is trading above it.
MoS (%) = (Intrinsic Value − Price) ÷ Intrinsic Value × 100
Step 1: Enter the current market price of the stock you are evaluating.
Step 2: Enter your estimated intrinsic value. You can use our Graham Number calculator, a DCF model, or any other valuation method.
Step 3: The margin of safety, a colour-coded verdict, a visual gauge, and a sensitivity table appear instantly as you type.
Step 4: Use the verdict as a signal, not a guarantee. A strong margin of safety reduces risk but never eliminates it.
What Is the Margin of Safety in Value Investing?
The margin of safety is the difference between a stock's intrinsic value and its current market price, expressed as a percentage of intrinsic value. It is the central concept of value investing, introduced by Benjamin Graham in Security Analysis (1934) and popularised in The Intelligent Investor (1949). Graham argued that buying a stock at a significant discount to its intrinsic value provides a buffer, a margin of safety, that protects investors against valuation errors, unforeseen events, and market volatility.
Warren Buffett, Graham's most famous student, has called the margin of safety the three most important words in investing. Unlike speculative approaches that rely on momentum or sentiment, value investing demands that investors know what they are buying and refuse to overpay. The margin of safety quantifies exactly how much of a discount you are getting, and therefore how much room for error you have.
The Margin of Safety Formula Explained
MoS (%) = (Intrinsic Value − Current Price) ÷ Intrinsic Value × 100
If a stock's intrinsic value is $100 and it trades at $70, the margin of safety is 30%. If it trades at $110, the margin is negative 10%, meaning you are paying a 10% premium over fair value. The formula is straightforward, but its power lies in the quality of the intrinsic value estimate feeding it.
Common methods for estimating intrinsic value include the Graham Number (a quick screen based on EPS and book value), discounted cash flow (DCF) analysis (which projects future free cash flows and discounts them back to present value), earnings power value (EPV), and asset-based valuation. Each has strengths and limitations. The margin of safety calculation itself is always the same; only the input quality varies.
How Much Margin of Safety Is Enough?
Graham typically required a margin of safety of at least 33% for common stocks and 10 to 20% for investment-grade bonds. The required cushion depends on the uncertainty of the intrinsic value estimate: the more difficult the business to value (e.g., early-stage companies, cyclical industries), the larger the required margin of safety. For straightforward, stable businesses with predictable cash flows, a 15 to 20% margin may be adequate.
Our calculator uses these thresholds as guidance: above 30% is a Strong Buy signal, 15 to 30% is a Buy, 0 to 15% is a Hold (potential interest but limited cushion), and below 0% is Overvalued (trading above estimated intrinsic value). These are not hard rules; they are starting points for further analysis. A 5% margin of safety on a rock-solid blue-chip may be more attractive than a 40% margin on a highly speculative company.
Using This Tool Alongside Other Value Calculators
The margin of safety calculator is most powerful when combined with a reliable intrinsic value model. Start with our Graham Number calculator to get a quick intrinsic value estimate, then plug that figure in here to see your margin of safety. For a deeper analysis, use a DCF model and feed that present value into this calculator.
Remember: the margin of safety is a risk-management tool, not a buy signal on its own. Always consider the quality of the business, the sustainability of its competitive advantage, management quality, and macroeconomic context before making any investment decision. This calculator assists analysis; it does not replace it.
Frequently Asked Questions About Margin of Safety
Benjamin Graham recommended at least 33% for common stocks. In practice, most value investors look for 20 to 50% depending on the certainty of their intrinsic value estimate. For highly predictable businesses (e.g., consumer staples, utilities), 15 to 20% may suffice. For less predictable companies (technology, biotech, cyclicals), many investors demand 40 to 50% or more. There is no universal number: the required margin reflects how confident you are in your valuation.
The most common approaches are: (1) Graham Number, the square root of 22.5 times EPS times book value per share, useful for traditional value stocks; (2) DCF analysis, projecting free cash flows 5 to 10 years forward and discounting at an appropriate rate (WACC); (3) Earnings Power Value, current normalised earnings divided by the cost of capital; (4) comparable company analysis, applying an industry average P/E or EV/EBITDA multiple. Each method produces a different estimate, so many investors average several models to reduce error.
Not necessarily. A very high margin of safety can signal genuine undervaluation, but it can also mean your intrinsic value estimate is wrong, the market knows something you do not (e.g., deteriorating fundamentals), or the stock is a value trap, a company that appears cheap but continues to decline. Always investigate why a stock is trading at a large discount before assuming it is an opportunity. The margin of safety reduces risk on accurate valuations; it cannot compensate for a flawed analysis.
The Graham Number is one method of estimating intrinsic value. The margin of safety is what you calculate after you have an intrinsic value estimate: it tells you how much of a discount the current market price represents. You can use our Graham Number calculator to generate an intrinsic value, then feed that number into this margin of safety calculator to see how the current price compares.
For a deeper dive, read our companion article: What Is the Margin of Safety? A Value Investor's Guide
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