The Margin of Safety calculator that actually pulls live data.

Estimate what a stock is actually worth from its earnings and growth, then see how big a discount you're getting at today's price. Enter a ticker and the inputs fill themselves.

By Guillermo Valles
Updated May 24, 2026
AAPL LogoAAPL
or
Earnings per share (TTM)
$
Current market price
$
Growth rate per year
%
Duration
Yrs
Exit P/E
x
Required return
%

Margin of Safety

Overvalued
-61.5%

61.5% above intrinsic value

Estimated intrinsic value$140.6
Current price$227.1
Dollar buffer per share-$86.5
Buy below (for 25% MOS)$105.5

Loaded AAPL. These are sample figures. The live add-in pulls current EPS, a growth estimate, and the real time price.

The Formula

The margin of safety formula

Once you have an intrinsic value estimate, the margin of safety is the gap between that value and the price, shown as a percentage.

Margin of Safety=
Intrinsic Value − Market PriceIntrinsic Value
Intrinsic value per share$140.6
Current market price$227.1
Margin of safety buffer$-86.5
Foundations

What margin of safety means

Margin of safety is the cushion between what you think a stock is worth and what you pay for it. The idea comes from Benjamin Graham and was carried forward by Warren Buffett: because every valuation rests on estimates that can be wrong, you use a buffer so that even a flawed estimate still leaves you protected.
Think of it as buying a dollar of value for seventy cents. If your analysis is off by a little, the buffer absorbs the error. If the market turns against you, you bought low enough that the downside is limited. The bigger the uncertainty in your estimate, the bigger the margin you should demand.
The Insight

What counts as a good margin of safety?

There is no single right number. It scales with how confident you are in your estimate and how predictable the business is.

Under 15%Thin

Thin (under 15%)

Little room for error. Only defensible for very stable, easy to forecast businesses you understand deeply.

20 to 30%Reasonable

Reasonable (20 to 30%)

The range most value investors target on quality companies they can model with confidence.

40%+Deep value

Deep value (40%+)

The cushion for volatile, misunderstood, or hard to forecast businesses, or for buying during market panics.

Worked Example

AAPL's Margin of Safety, line by line

Once you have the intrinsic value, the margin of safety tells you how much discount you're getting — and whether it's worth buying.

AAPL Logo

AAPL Inc.

AAPLLive Calculator View$227.14
STEP 01

Project future EPS

Current EPS: $6.42 Growth: 9.0% for 10 Years Future EPS = EPS × (1 + g)ⁿ Future EPS = $6.42 × (1 + 9.0%)10

→ $15.20
STEP 02

Estimate future share price

Future EPS: $15.20 Exit PE: 24.0x Future Price = Future EPS × PE Future Price = $15.20 × 24

→ $364.76
STEP 03

Discount to intrinsic value

Future Price: $364.76 Required Return: 10.0% Intrinsic Value = Future Price / (1 + r)ⁿ IV = $364.76 / (1 + 10.0%)10

→ $140.63
STEP 04

Calculate margin of safety

Intrinsic Value: $140.63 Current Price: $227.14 MOS = (IV − Price) / IV MOS = ($140.63 − $227.14) / $140.63

→ -61.5% Premium
Pitfalls

Common mistakes to avoid

If your margin of safety feels off, it's almost always one of these.

Mistake 01

Treating one estimate as precise

Intrinsic value is a range, not a single number. Run a low, base, and high case rather than anchoring to one figure.
Mistake 02

Ignoring business quality

A 25 percent margin on a fragile, cyclical company is riskier than the same margin on a durable compounder. The quality of the business changes how much cushion you need.
Mistake 03

Using an aggressive growth rate

Plugging in a high growth rate inflates intrinsic value and erases your margin without you noticing. Lean conservative on every assumption.
Mistake 04

Forgetting the discount rate

A future price is not a present value. Skipping the discount step makes nearly every stock look cheaper than it is.
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Guillermo Valles

Guillermo Valles

Founder•Wisesheets•Former Financial Analyst

Guillermo Valles is the founder and CEO of Wisesheets, a former financial analyst at SmartCentres REIT, and a graduate of the Schulich School of Business. After years of building financial models and manually gathering company data in spreadsheets, he founded Wisesheets in 2020 to make financial analysis faster, more transparent, and easier to verify. This calculator uses the same financial data infrastructure that powers Wisesheets’ Excel and Google Sheets tools, drawing from SEC filings and reconciled market data. Its calculations and methodology are reviewed quarterly by the Wisesheets team.

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