The 10 Most Important Financial Ratios Every Investor Should Know

Financial ratios are the language of investing. You don't need to know hundreds of them — most professional analysts rely on a core set of about 10 that tell you almost everything you need to know about a company's value, profitability, financial health, and growth potential.

Here are the 10 ratios that matter most, with real examples so you can start using them today. If you're just starting out, pair this with our guide on how to evaluate a stock in 5 minutes.

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1. Price-to-Earnings Ratio (P/E)

What it tells you: How much investors are willing to pay for $1 of earnings.

P/E = Stock Price ÷ Earnings Per Share (EPS)

Real example (as of early 2025):

• Apple (AAPL): $230 stock price ÷ $6.97 EPS = 33.0x P/E
• Ford (F): $10.50 stock price ÷ $1.76 EPS = 6.0x P/E
• S&P 500 average: ~22-24x

How to use it:

• Compare within the same industry (tech P/Es are naturally higher than auto P/Es)
• A low P/E might mean undervalued or that the business is declining
• A high P/E might mean overvalued or that growth justifies the premium

We covered this one in depth in our P/E ratio deep dive.

⚠️ Pitfall: P/E is useless for unprofitable companies (you can't divide by zero or negative earnings). Use Price-to-Sales instead.

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2. Price-to-Book Ratio (P/B)

What it tells you: How much you're paying relative to the company's net asset value (book value).

P/B = Stock Price ÷ Book Value Per Share

Real example:

• JPMorgan Chase (JPM): $245 ÷ $115.40 book value = 2.12x P/B
• Bank of America (BAC): $44 ÷ $34.80 = 1.26x P/B
• Apple (AAPL): $230 ÷ $3.75 = 61.3x P/B

How to use it:

• Most useful for banks and financial companies where assets are marked to market
• A P/B below 1.0 means you're buying the company for less than its assets are worth on paper — either a bargain or a value trap
• For asset-light companies (tech, services), P/B is less meaningful because their value is in intellectual property, not physical assets

⚠️ Pitfall: Book value doesn't capture intangible assets like brand value, patents, or network effects. Coca-Cola's brand alone is worth more than its book value.

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3. Return on Equity (ROE)

What it tells you: How efficiently management turns shareholder equity into profit.

ROE = Net Income ÷ Shareholders' Equity × 100

Real example:

• Apple (AAPL): $93.7B net income ÷ $56.7B equity = 165% ROE
• Microsoft (MSFT): $88.1B ÷ $268.5B = 32.8% ROE
• Walmart (WMT): $15.5B ÷ $83.9B = 18.5% ROE

How to use it:

• Above 15% = generally strong
• Above 20% = excellent
• Consistently high ROE over 5+ years = competitive advantage (Warren Buffett's favorite signal)

⚠️ Pitfall: Apple's 165% ROE is artificially inflated by stock buybacks reducing equity. Always check why ROE is high — high profitability vs. financial engineering.

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4. Debt-to-Equity Ratio (D/E)

What it tells you: How much the company relies on debt versus shareholder equity to finance operations.

D/E = Total Liabilities ÷ Shareholders' Equity

Real example:

• Google/Alphabet (GOOGL): $119.1B ÷ $315.4B = 0.38x — very conservatively financed
• AT&T (T): $260.2B ÷ $123.8B = 2.10x — heavily leveraged (common for telecoms)
• Apple (AAPL): $308.0B ÷ $56.7B = 5.43x — looks scary but misleading (see our balance sheet guide for why)

How to use it:

• Below 1.0 = conservatively financed
• 1.0 to 2.0 = moderate leverage
• Above 2.0 = investigate further — is the debt manageable given cash flow?
• Compare within industries (utilities and telecoms naturally carry more debt)

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5. Current Ratio

What it tells you: Can the company pay its bills due in the next 12 months?

Current Ratio = Current Assets ÷ Current Liabilities

Real example:

• Google (GOOGL): $163.6B ÷ $81.8B = 2.00 — very healthy
• Johnson & Johnson (JNJ): $54.6B ÷ $50.5B = 1.08 — adequate
• Tesla (TSLA): $49.1B ÷ $28.7B = 1.71 — comfortable

How to use it:

• Above 2.0 = strong liquidity (though too high might mean idle cash)
• 1.0 to 2.0 = generally healthy
• Below 1.0 = potential liquidity risk (but context matters — Apple operates fine below 1.0)

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6. Dividend Yield

What it tells you: How much income you receive relative to the stock price.

Dividend Yield = Annual Dividend Per Share ÷ Stock Price × 100

Real example:

• Verizon (VZ): $2.71 annual dividend ÷ $43.50 stock price = 6.23% yield
• Coca-Cola (KO): $1.94 ÷ $62 = 3.13% yield
• Apple (AAPL): $1.00 ÷ $230 = 0.43% yield
• Amazon (AMZN): $0 ÷ $225 = 0% yield

How to use it:

• High yield (above 5%) = attractive income but investigate sustainability — the company might be in trouble and the dividend could be cut
• The "sweet spot" for dividend growth investing is typically 2-4% yield with consistent dividend increases
• A suddenly high yield often means the stock price dropped, not that the dividend increased

If you're building an income portfolio, check out our guide on building a dividend portfolio for $500/month.

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7. PEG Ratio (Price/Earnings to Growth)

What it tells you: Whether the P/E ratio is justified by the company's growth rate.

PEG = P/E Ratio ÷ Expected Annual EPS Growth Rate

Real example:

• Nvidia (NVDA): 55x P/E ÷ 40% expected growth = 1.38 PEG
• Coca-Cola (KO): 24x P/E ÷ 6% expected growth = 4.0 PEG
• Meta (META): 27x P/E ÷ 20% expected growth = 1.35 PEG

How to use it:

• PEG below 1.0 = potentially undervalued relative to growth
• PEG of 1.0 = fairly valued
• PEG above 2.0 = potentially overvalued even accounting for growth

Peter Lynch popularized this ratio, and it's one of the best ways to compare companies with different growth rates on a level playing field.

⚠️ Pitfall: Growth estimates are estimates. Garbage in, garbage out. Use consensus analyst estimates, not the most optimistic projections.

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8. Earnings Per Share (EPS)

What it tells you: How much profit the company generates per share of stock.

EPS = Net Income ÷ Shares Outstanding

Real example (trailing twelve months):

• Apple (AAPL): $93.7B ÷ 15.12B shares = $6.20 EPS
• Microsoft (MSFT): $88.1B ÷ 7.43B shares = $11.86 EPS
• Amazon (AMZN): $59.2B ÷ 10.5B shares = $5.64 EPS

How to use it:

• EPS itself isn't that useful as a standalone number — $6.20 EPS means nothing without knowing the stock price
• EPS growth trend is what matters: is it increasing year over year?
• Always use diluted EPS (accounts for stock options and convertible securities) rather than basic EPS
• Compare quarter-over-quarter and year-over-year growth

| Company | 2022 EPS | 2023 EPS | 2024 EPS | 2-Year Growth | |---------|----------|----------|----------|---------------| | Apple | $6.15 | $6.42 | $6.97 | +13.3% | | Microsoft | $9.21 | $11.07 | $11.86 | +28.8% | | Amazon | -$0.27 | $2.90 | $5.64 | N/A (turnaround) |

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9. Free Cash Flow Yield

What it tells you: The "real" earnings yield — how much actual cash the business generates relative to its market value.

FCF Yield = Free Cash Flow ÷ Market Capitalization × 100

Real example:

• Apple (AAPL): $111B FCF ÷ $3.47T market cap = 3.2% FCF yield
• Google (GOOGL): $72.4B FCF ÷ $2.34T market cap = 3.1% FCF yield
• Meta (META): $52.1B FCF ÷ $1.65T market cap = 3.2% FCF yield

How to use it:

• FCF is harder to manipulate than earnings (cash is cash — you either have it or you don't)
• FCF yield above 5% = potentially undervalued
• FCF yield above 8% = either a bargain or the market expects cash flow to decline
• Compare to the 10-year Treasury yield (~4.2% in early 2025) — if FCF yield is lower than the risk-free rate, you're paying a premium for growth

Why it matters more than P/E: A company can report high earnings while burning cash (through accounting tricks). Free cash flow can't be faked as easily. It's the money available to pay dividends, buy back shares, reduce debt, or reinvest in the business.

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10. Price-to-Sales Ratio (P/S)

What it tells you: How much investors pay per dollar of revenue.

P/S = Market Capitalization ÷ Annual Revenue

Real example:

• Apple (AAPL): $3.47T ÷ $391B = 8.9x P/S
• Walmart (WMT): $735B ÷ $648B = 1.1x P/S
• Palantir (PLTR): $250B ÷ $2.9B = 86.2x P/S

How to use it:

• Most useful for unprofitable or early-stage companies where P/E doesn't work
• Below 1.0 P/S = you're paying less than $1 for every $1 of sales — potential deep value
• Above 10x P/S = market expects enormous margin expansion or revenue growth
• Palantir at 86x P/S needs to grow into a massively larger company to justify its valuation

⚠️ Pitfall: Revenue doesn't equal profit. A company with $10B in revenue and -$2B in losses is very different from one with $10B in revenue and $3B in profit.

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Quick Reference Cheat Sheet

| Ratio | Formula | "Good" Range | Best For | |-------|---------|-------------|----------| | P/E | Price ÷ EPS | 15-25x (market avg) | Profitable companies | | P/B | Price ÷ Book Value | Below 3x | Banks, asset-heavy | | ROE | Net Income ÷ Equity | Above 15% | Management quality | | D/E | Liabilities ÷ Equity | Below 2x | Financial health | | Current Ratio | Current Assets ÷ Current Liabilities | 1.5-2.5x | Liquidity | | Dividend Yield | Dividend ÷ Price | 2-4% (growth) | Income investors | | PEG | P/E ÷ Growth Rate | Below 1.5 | Growth at fair price | | EPS | Net Income ÷ Shares | Trending up | Earnings trajectory | | FCF Yield | FCF ÷ Market Cap | Above 5% | True cash generation | | P/S | Market Cap ÷ Revenue | Below 5x | Unprofitable growth |

How to Use These Together

No single ratio tells the full story. Here's a quick multi-ratio framework:

1. Start with P/E — Is the valuation reasonable?
2. Check PEG — Is the P/E justified by growth?
3. Verify with FCF Yield — Are earnings backed by real cash?
4. Assess risk with D/E and Current Ratio — Can the company survive a downturn?
5. Evaluate management with ROE — Are they using capital efficiently?

Master these 10 ratios and you'll analyze stocks better than 90% of retail investors. Combine them with knowing how to read a balance sheet and understanding stock charts, and you've got a complete analytical toolkit.

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