Stock Margin of Safety Calculator
Enter your own intrinsic-value estimate for the fastest result—or optionally estimate one from owner earnings and discounted expected cash flows. Every assumption stays visible.
Margin of safety
20.00%
$80.00 is $20.00 below the $100.00 estimate.
- Intrinsic value used
- $100.00
- Value source
- Entered estimate
- Dollar gap (value − price)
- +$20.00
- Price as % of value
- 80.00%
- Move from price to value
- +25.00%
Owner-earnings valuation
$46.33 + $46.97 = $93.30
- Owner earnings today
- $6.00
- Year 1 owner earnings
- $6.30
- Year 10 owner earnings
- $9.77
- PV of years 1–10
- $46.33
- PV after year 10
- $46.97
- Share from after year 10
- 50.34%
The last percentage shows how much of the estimate depends on cash flows beyond year 10. It is an uncertainty diagnostic, not a pass/fail rule.
Calculation
($100.00 − $80.00) ÷ $100.00 × 100 = 20.00%
The intrinsic-value estimate is the denominator. That is why a 20% margin of safety from $80 to $100 is not the same as the 25% move needed to rise from $80 to $100.
Method and sources. Arithmetic on your inputs — not a valuation, price target, or investment recommendation.
Cross-check the valuation
The percentage is only as useful as the estimate behind it.
Use the full DCF calculator as a second method with company-level free cash flow, explicit forecast years, terminal value, cash, debt, and share count. Different input semantics are not carried automatically.
Cross-check with a full DCFHow to calculate a stock's margin of safety
Enter the current share price
Use the price for the same share class and currency as your per-share valuation. CalcStocks does not fetch or refresh market prices.
Enter your intrinsic-value estimate
Use your own estimate for the shortest route. If you do not have one, switch to owner-earnings mode and enter four explicit cash-flow assumptions.
Audit the percentage and dollar gap
The calculator subtracts price from value, divides by value, and shows every substituted number. A negative result means price is above the estimate.
Owner earnings: Buffett's cash-flow starting point
In Berkshire Hathaway's 1986 shareholder letter, Warren Buffett described owner earnings as reported earnings plus depreciation, depletion, amortization, and certain other non-cash charges, minus the average capital spending needed to maintain competitive position and unit volume. Added working capital may also need to be subtracted. He stressed that maintenance capital is an estimate and that accounting is a starting point, not a substitute for business judgment.
Owner earnings = reported earnings + qualifying non-cash charges − maintenance capital spending − added working capital
How the optional intrinsic-value estimate works
Berkshire's 1992 letter describes value as expected cash inflows and outflows discounted at an appropriate rate, while warning that the analyst must estimate an equity's future cash flows. CalcStocks grows the entered owner earnings for ten annual periods, discounts each amount, and adds a continuing value after year 10 using the entered terminal growth rate.
Estimated value = Σ₁¹⁰ owner earningsₜ ÷ (1 + discount rate)ᵗ + continuing value₁₀ ÷ (1 + discount rate)¹⁰
The fixed ten-year horizon, constant explicit growth rate, and continuing-value formula are CalcStocks implementation choices. Buffett did not publish this calculator or a universal discount rate. If the business is complex, unstable, or outside your ability to forecast, the most Buffett-consistent result may be not to force a valuation.
Margin of safety formula for stocks
For this stock-investing definition, margin of safety is the discount between current share price and estimated intrinsic value, measured against the intrinsic value. Multiply by 100 to express the result as a percentage.
Margin of safety = (intrinsic value − current price) ÷ intrinsic value × 100
At a current price of $80 and an intrinsic-value estimate of $100, the dollar gap is $20 and the margin of safety is $20 ÷ $100 = 20%.
Margin of safety is not the same as upside
The two percentages use different denominators. Margin of safety divides the $20 gap by the $100 value estimate. The move from price to value divides the same $20 by the $80 starting price, producing 25%.
Margin of safety: $20 ÷ $100 = 20% · Move to value: $20 ÷ $80 = 25%
What a negative margin of safety means
If current price is above the entered intrinsic value, the result is negative. A $120 price against a $100 estimate gives ($100 − $120) ÷ $100 = −20%, meaning the price is at a 20% premium to that estimate. It is a comparison, not a forecast of a 20% loss.
The hard part is the intrinsic-value estimate
The subtraction is exact, but the valuation is an estimate. Cash-flow forecasts, discount rates, normalized owner earnings, maintenance capital, working capital, dilution, and share count can all change it. A wide calculated gap cannot repair a weak or stale valuation.
Margin of safety examples
These examples make the denominator and the signed result explicit.
- 20% discount. A price of $80 against a $100 value estimate gives ($100 − $80) ÷ $100 = 20%.
- Owner-earnings identity check. Flat owner earnings of $10 per share, 0% growth, a 10% discount rate, and 0% continuing growth produce $100: the present value of ten annual cash flows plus the discounted continuing value equals the same $10 ÷ 10% perpetuity.
- Equal price and value. A price of $100 against a $100 estimate gives a 0% margin of safety.
- 20% premium. A price of $120 against a $100 estimate gives −20%. The move back to $100 would be −16.67% because that separate percentage starts from $120.
- Primary-source ratio test. In Warren Buffett's 1984 Columbia essay, paying $80 million for $400 million of properties illustrates a large gap: ($400m − $80m) ÷ $400m = 80%. His $80m-for-$83m contrast is only about 3.61%.
Stock margin of safety questions
The formula, interpretation, valuation limits, and the separate accounting meaning.
Basics
What is margin of safety in stock investing?
It is the gap between a stock's current market price and an investor's estimate of intrinsic value. This calculator expresses that gap in dollars and as a percentage of the entered intrinsic value.
How do you calculate a stock's margin of safety?
Subtract current share price from estimated intrinsic value, divide the difference by intrinsic value, and multiply by 100. A price of $80 and value estimate of $100 produce a 20% margin of safety.
What numbers do I need for this calculator?
For the fastest route, enter current share price and your own intrinsic-value estimate per share. Optional owner-earnings mode instead needs current owner earnings per share, a ten-year growth assumption, a discount rate, and continuing growth.
How do I find margin of safety in dollars?
Subtract current price from intrinsic value. If value is $100 and price is $80, the dollar gap is $20 per share. If price is $120, the signed gap is −$20, which is a premium to the estimate.
How do I find margin of safety as a percentage?
Divide the dollar gap by the intrinsic-value estimate and multiply by 100. The value estimate, not current price, is the denominator in this calculator.
Is this the same as accounting margin of safety?
No. Accounting and break-even analysis often compare actual or forecast sales with break-even sales, sometimes in dollars or units. This page is only for the stock-investing comparison between share price and estimated intrinsic value.
Formula
What is the stock margin of safety formula?
Margin of safety = (intrinsic value − current price) ÷ intrinsic value × 100. The calculator uses unrounded inputs and rounds displayed percentages to two decimal places.
What are owner earnings in Buffett's definition?
Buffett's 1986 letter starts with reported earnings, adds depreciation, depletion, amortization, and certain other non-cash charges, then subtracts average maintenance capital spending and any added working capital needed to maintain the business. The maintenance amount requires judgment.
How does the optional intrinsic-value estimate work?
It grows owner earnings for ten years, discounts each annual amount, and adds a discounted continuing value based on year-10 owner earnings and the entered terminal growth rate. The result then becomes the value input for the margin calculation.
Is this a Warren Buffett intrinsic value formula?
No. Buffett published owner-earnings and discounted-cash-flow principles, not this four-input calculator or a universal discount rate. The ten-year horizon and continuing-value implementation are transparent CalcStocks choices.
What discount rate should I use?
The calculator cannot prescribe one. The rate represents the return required to exchange money today for uncertain future owner earnings. Test a range, keep it above terminal growth, and do not use precision in the output to disguise uncertainty in the assumption.
What does the continuing-value share mean?
It is the percentage of estimated intrinsic value supplied by cash flows after year 10. A larger share means more of the estimate depends on the terminal growth and discount-rate assumptions; the calculator shows it as an uncertainty diagnostic, not a verdict.
Why is intrinsic value the denominator?
The calculation asks what share of the estimated value is not reflected in the current price. Dividing by value makes an $80 price against a $100 estimate a 20% discount to that estimate.
Why is a 20% margin of safety equal to 25% upside in the example?
They start from different bases. The $20 discount is 20% of the $100 value estimate, but a $20 increase is 25% of the $80 current price. Margin of safety and upside are not interchangeable.
What happens when price equals intrinsic value?
The dollar gap and margin of safety are both zero. That only means the two entered numbers match; it does not establish that either number is correct or predict what the market will do.
Can current price be above intrinsic value?
Yes. The calculator then reports a negative margin of safety and a negative dollar gap. In plain language, the price is at a premium to the entered estimate.
Does a negative margin of safety predict a loss?
No. It is a comparison between today's price and one valuation estimate. The estimate may change, the business may perform differently, and market price can move for many reasons.
Interpretation
What is a good margin of safety percentage?
There is no universal percentage. The uncertainty of the valuation, business stability, balance sheet, cyclicality, competitive position, and investor's method all matter. This calculator deliberately does not label a result good, safe, or sufficient.
Should every stock have a 20% or 30% margin of safety?
No single threshold fits every company or valuation method. A precise-looking percentage can be misleading when the underlying cash flows or assumptions are highly uncertain. Treat any hurdle as your assumption, not a universal rule.
Does a margin of safety prevent investment losses?
No. Intrinsic value can be estimated incorrectly, business value can deteriorate, dilution can change per-share value, and market prices can stay below an estimate for a long time. The calculation is not insurance.
What if my intrinsic-value estimate changes?
Enter the updated estimate and the result will recalculate. Keep a record of why the valuation changed; changing the estimate only to preserve a desired margin defeats the purpose of the comparison.
Can I compare two stocks by margin of safety alone?
Not reliably. Two identical percentages can rest on very different business quality, debt, forecast uncertainty, cyclicality, dilution risk, or valuation methods. Review the assumptions and company fundamentals behind each estimate.
Limits & privacy
Does this calculator estimate intrinsic value?
Optionally. Select the owner-earnings mode for a transparent ten-year discounted-cash-flow estimate, or keep the default route and supply your own value. Neither route verifies that the assumptions fit the company.
Does the calculator fetch a live stock price?
No. CalcStocks does not look up tickers or request market data. Enter the price you want to analyze and check its date and share class yourself.
Does CalcStocks store the numbers I enter?
No. The arithmetic runs in your browser and the inputs are not sent to the server. A copied share link includes the price and value in its URL, so review the link before sending it.
Is the result investment advice or a buy signal?
No. It is arithmetic on two visitor-entered numbers. CalcStocks does not verify the valuation, know your circumstances, recommend a security, or tell you when to buy or sell.
Continue the valuation work
Estimate value with explicit assumptions, then compare methods rather than treating one percentage as a conclusion.
Intrinsic Value Calculator
Build a seven-to-ten-year earnings forecast, inspect every year, and turn your assumptions into a Graham estimate and sensitivity range.
DCF Calculator
Two-stage discounted cash flow with a fade period, a reverse DCF that shows the growth the price already implies, and a full sensitivity grid.
Benjamin Graham Formula Calculator
Graham's growth formula, the bond-yield revised version, and the Graham Number — all three on one page, clearly labelled as the different things they are.
Method, primary sources, and limitations
Built by CalcStocks' owner and checked with automated math and page-interaction tests. No outside expert review is claimed. Direct mode performs (value − price) ÷ value. Optional estimate mode discounts ten years of owner earnings plus a continuing value, then applies the same ratio. Calculations use unrounded inputs; displayed currency and percentages are rounded to two decimals.
Primary-source worked example
Warren Buffett's 1984 Columbia essay contrasts paying $80 million for only $83 million of value with paying $80 million for $400 million of value. Applying the displayed ratio to the larger gap gives:
($400m − $80m) ÷ $400m × 100 = 80%
The ratio is unitless, so the same arithmetic applies to per-share values. For the optional estimator, automated tests also confirm that flat $10 owner earnings, 0% growth, a 10% discount rate, and 0% continuing growth equal $100—the $10 ÷ 10% perpetuity identity.
- Warren Buffett, The Superinvestors of Graham-and-Doddsville — the primary authored essay containing the $80 million, $83 million, and $400 million margin-of-safety examples.
- Berkshire Hathaway 1986 shareholder letter — defines owner earnings and explains why maintenance capital expenditure and working-capital needs require investor judgment.
- Berkshire Hathaway 1992 shareholder letter — explains value through discounted expected cash flows, warns that equity cash flows must be estimated, limits valuation to understandable businesses, and describes insisting on a purchase-price margin.
- Columbia Business School value-investing history — documents the Graham and Dodd provenance and summarizes margin of safety as price being lower relative to intrinsic value.
Sources checked . The cited authors and organizations did not review or endorse CalcStocks.
The calculator cannot determine whether owner earnings, growth, discount rate, terminal growth, or an entered intrinsic value are sound for a company. It does not model changing share count, net debt, cyclicality, scenario probabilities, or business deterioration. The ten-year DCF is a CalcStocks implementation, not a formula prescribed or endorsed by Buffett. A margin of safety does not guarantee against loss.