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How to Tell If a Stock Is Cheap or Expensive? Simple Roadmap To Follow

M
Jan 22, 2026 · 19:59

Hi everyone,

We have all been there. You find a stock you love. The story is great and the fundamentals look solid. But when you pull up the chart, you see a vertical line going straight up.

Suddenly you freeze. Is it too late to buy? Or are you missing out?

I built a 4-step valuation roadmap to filter out expensive stocks in seconds. I visualized the process into the flowchart attached.

Here is the detailed breakdown of how to use it.

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Step 1: The Context Check (The Moat)

Before looking at the P/E ratio, check the durability of the business.

\* Wide Moat: Companies like ARM or Microsoft. High switching costs or network effects. These deserve a premium valuation.

\* No Moat: Companies like Airlines. They compete strictly on price. These are capital destruction machines over the long term.

Rule: If the Moat is None, stop. The price doesn't matter if the business is indefensible.

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Step 2: The Profit Fork

You cannot value all stocks the same way. You must ask if it is actually making money.

\* Path A (Profitable): Value these based on Earnings (P/E, PEG).

\* Path B (Unprofitable): Value these based on Revenue and Survival (P/S, Cash).

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Step 3: The Valuation Rules

For Profitable Stocks (Path A)

P/E is useless in a vacuum. A P/E of 50 is cheap if growth is 50%. A P/E of 10 is expensive if growth is 0%.

Use the PEG Ratio (P/E divided by EPS Growth).

\* PEG under 1.0: Undervalued.

\* PEG around 1.5: Fair Value.

\* PEG over 2.0: Expensive.

\* Note: For dividend stocks, use the PEGY Ratio to give them credit for the yield.

For Unprofitable Stocks (Path B)

Use Price-to-Sales (P/S).

\* P/S under 10: Generally cheap for high-growth tech.

\* P/S over 50: The Danger Zone. At 50x sales, the company is priced for absolute perfection.

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Step 4: The Quality and Survival Check

If a stock looks expensive (PEG over 2.0), is it an automatic sell? Not necessarily. It might be a premium asset.

The Margin Test (For Profitable Stocks)

High prices require high Gross Margins.

\* Software needs over 70% margins.

\* Hardware needs over 40% margins.

If the margins are low and the price is high, it is a bubble.

The Cash Runway (For Unprofitable Stocks)

Check the Total Cash divided by Annual Burn.

\* Over 2 years: Safe.

\* Under 1 year: Dilution Risk. They will likely issue new shares to raise cash, which crushes your stock price.