PEG Ratio Explained

By Ryan O'Connell, CFA, FRM Published October 20, 2026
Table of Contents

    A stock with a price-to-earnings ratio of 15 can look less expensive than one trading at 30 times earnings. But what if the second company is expected to grow earnings much faster? The PEG ratio brings that growth assumption into the comparison. Understanding its inputs helps you distinguish a useful valuation screen from an attractive number built on an optimistic forecast.

    What Is the PEG Ratio?

    The price/earnings-to-growth ratio, or PEG ratio, divides a stock’s P/E ratio by its annual earnings-per-share growth rate. Investors commonly use expected growth to assess how a valuation multiple compares with a company’s projected earnings expansion.[1]

    The price-to-earnings ratio measures share price relative to annual earnings per share. PEG adds a growth input, helping explain why a stock with a higher P/E can have a lower growth-adjusted multiple.

    What PEG Can Tell You

    A PEG of 1 means the P/E multiple equals the annual growth rate’s whole-percentage number: for example, a P/E of 30 divided by 30% growth gives 30 / 30 = 1. That equality is a screening benchmark; it does not establish fair value.

    The PEG Ratio Formula

    PEG Using Expected Earnings Growth
    PEG = P/E ratio / Expected annual EPS growth rate (%)
    Use the whole-percentage growth number: enter 15 for 15% growth.

    Start with P/E = Share price / EPS. Identify whether the earnings per share figure is trailing or forecast, basic or diluted, and reported under GAAP or adjusted. Then identify the growth estimate’s starting year and forecast horizon.

    The percentage convention matters. With a P/E of 30 and expected annual EPS growth of 30%, PEG = 30 / 30 = 1.00. Dividing by 0.30 instead produces 100, a different scale. Schwab’s worked examples use the same whole-percentage convention.[4]

    Watch: PEG Ratio in Stock Market Explained | Price/Earnings-to-Growth Ratio

    PEG Ratio Example: Higher P/E, Lower PEG

    Two Hypothetical Businesses

    Assume two profitable companies in the same industry. All prices, earnings, and forecasts below are hypothetical. For both companies, calculate forward P/E using next fiscal year’s forecast diluted EPS. Measure expected annual EPS growth over the three years following that forecast base year.

    Comparing hypothetical companies using the same earnings and growth conventions
    Input or calculation Faster-growing company Slower-growing company
    Assumed share price $120 $60
    Forecast diluted EPS in the base year $4 $4
    Forward P/E $120 / $4 = 30 $60 / $4 = 15
    Expected annual EPS growth after the base year 30% 5%
    PEG ratio 30 / 30 = 1.00 15 / 5 = 3.00

    The company trading at 30 times earnings has the lower PEG. Its assumed growth rate is six times higher, while its P/E is only twice as high. The lower-P/E company therefore carries the higher multiple relative to the growth assumption.

    This comparison identifies a question to investigate: how credible and sustainable is the faster growth? The calculation alone cannot establish which stock offers the better investment.

    How to Interpret PEG Ratios

    For a positive P/E and positive growth rate, the familiar interpretation centers on a PEG of one. Treat the following ranges as shorthand for comparing inputs.

    Common PEG interpretations and their practical limits
    PEG value What the calculation shows What to investigate
    Between 0 and 1 P/E is below the annual growth percentage number. Whether growth is realistic and the lower valuation reflects business risk.
    About 1 P/E approximately matches that growth number. Whether profitability, risk, and investment requirements support the price.
    Above 1 P/E exceeds that growth number. Whether the company has qualities that justify the higher relative multiple.

    Damodaran’s valuation analysis explains why a P/E below expected growth does not automatically establish undervaluation. Risk and payout still matter, and the relationship between growth and value is more complex than a fixed PEG threshold.[3]

    Which Growth Rate Should You Use?

    Read the data provider’s definition before comparing PEG values. Fidelity’s research glossary, for example, specifies forward P/E divided by projected annual EPS growth over three to five years.[2] Other calculations can use historical growth or a different forecast horizon. Record the P/E earnings basis, growth starting point, period, estimate source, and observation date.

    A trailing P/E combined with forecast growth and a forward P/E combined with forecast growth are distinct conventions. Make the choice explicit and apply it consistently across companies. Check that the growth forecast starts from the intended EPS base rather than silently changing that base when switching P/E measures.

    Annual Growth Is Different From Total Growth

    For a separate hypothetical example, suppose EPS is forecast to rise from $4 in a specified base year to $8 five years later. That is a total increase of ($8 / $4 − 1) × 100 = 100%, spread across five years. The annualized rate is:

    Annualized EPS Growth in This Example
    [($8 / $4)1/5 − 1] × 100 ≈ 14.87%
    The compound annual rate implied by the two positive EPS endpoints.

    With a P/E of 30, using the unrounded annualized rate gives PEG = 30 / 14.8698355 ≈ 2.02. Incorrectly dividing by the cumulative 100% increase produces 0.30. A five-year PEG calculation needs an annual growth input, not the total percentage increase across five years.

    Test How Much the Forecast Matters

    Growth estimates can be revised and can prove too optimistic or pessimistic.[4] The following scenarios hold P/E fixed to isolate the effect of changing the growth assumption.

    Hypothetical PEG sensitivity with P/E held at 30
    Expected annual EPS growth Calculation PEG
    30% 30 / 30 1.00
    20% 30 / 20 1.50
    15% 30 / 15 2.00
    10% 30 / 10 3.00
    5% 30 / 5 6.00

    Cutting the growth assumption from 30% to 15% doubles PEG from 1 to 2. In an actual market, the share price and P/E might also change after a forecast revision; this table is an arithmetic sensitivity exercise.

    Real Company Examples: Inspect the Earnings Input

    Meta: Historical Growth Is Not a Forecast

    Meta reported diluted EPS of $14.87 for 2023 and $23.86 for 2024 in its 2024 Form 10-K.[5] Using those rounded figures, historical growth was ($23.86 / $14.87 − 1) × 100 ≈ 60.46%.

    That calculation describes one completed year. Using 60.46 as the denominator of a forecast-based PEG would require an additional assumption that this rate represents the future period being evaluated. The reported result itself does not establish that assumption.

    Coca-Cola: GAAP and Adjusted Growth Differ

    Coca-Cola’s 2024 Form 10-K reports diluted GAAP EPS, while its earnings releases also present comparable EPS identified as non-GAAP.[6][7][8]

    Coca-Cola historical EPS growth, calculated from rounded reported figures
    EPS basis 2023 2024 Growth calculation
    GAAP diluted EPS $2.47 $2.46 ($2.46 / $2.47 − 1) × 100 ≈ −0.40%
    Comparable EPS, non-GAAP $2.69 $2.88 ($2.88 / $2.69 − 1) × 100 ≈ 7.06%

    The comparable calculation agrees with the company’s reported whole-percentage growth of 7%. The GAAP calculation shows a slight decline. These historical inputs would lead to very different PEG interpretations, so the earnings definition must remain visible.

    Examine the adjustments before using an adjusted growth rate. SEC staff guidance explains that inconsistent adjustments between periods can mislead and that non-GAAP measures may differ across companies.[9] Neither company example supplies a current PEG quotation or a future growth estimate.

    PEG Ratio vs. P/E Ratio

    P/E Ratio

    • Divides share price by annual EPS.
    • Shows the valuation multiple on the selected earnings base.
    • Requires context about growth, risk, and earnings quality.

    PEG Ratio

    • Divides that P/E by an annual EPS growth-rate number.
    • Makes a selected growth assumption explicit.
    • Adds sensitivity to the growth estimate and its measurement period.

    Use P/E to understand the earnings multiple and PEG to examine that multiple alongside growth. A PEG screen can also help identify assumptions to investigate in a fuller discounted cash flow analysis.

    How to Use PEG in Stock Analysis

    1. Label the earnings base. Record the P/E date, trailing or forecast period, and EPS definition.
    2. Inspect the growth estimate. Identify who produced it, its starting EPS, and whether it is a one-year rate or a multiyear annualized projection.
    3. Calculate and compare consistently. Use the whole-percentage convention and comparable inputs for peer companies.
    4. Stress the assumption. Recalculate with a lower plausible growth rate and ask whether the investment case still holds.
    5. Check the business behind the ratio. Examine free cash flow and leverage measures such as the debt-to-equity ratio, rather than allowing one growth estimate to carry the entire analysis.

    The practical purpose is to guide further fundamental analysis: understand what must happen for the growth assumption to be achieved.

    Common PEG Ratio Mistakes

    • Entering a decimal percentage. Use 15 for 15% growth in the conventional formula.
    • Treating one as a valuation law. A PEG below one still requires investigation of forecasts, risk, and investment needs.
    • Mixing earnings definitions. A GAAP-based P/E and adjusted EPS growth can describe different earnings bases.
    • Using cumulative growth. Convert a multiyear change into an annualized rate before calculating PEG.
    • Extending a temporary rebound indefinitely. Check whether a strong growth figure reflects an unusually weak starting year.
    • Confusing slowing growth with falling earnings. Growth declining from 20% to 10% remains positive. At a fixed P/E of 20, PEG rises from 20 / 20 = 1 to 20 / 10 = 2.

    Limitations: When PEG Can Mislead

    Check for an Unusable Denominator

    At 0% growth, PEG is undefined because the calculation divides by zero. With a positive P/E of 20 and earnings growth of −5%, the quotient is 20 / (−5) = −4. That negative result is unsuitable for the usual positive-growth valuation ranking.

    Nonpositive earnings also disrupt the interpretation. If the selected EPS base is zero, P/E is undefined; if it is negative, the mechanical negative multiple does not support the usual PEG comparison. Fidelity’s documented PEG screening universe requires positive EPS.[2] A calculation using forecast positive earnings for a turnaround must be labeled and assessed on that separate basis.

    Growth quality matters. Businesses can need different amounts of investment to achieve the same growth. Damodaran’s analysis shows that risk and reinvestment efficiency continue to affect PEG.[3] Measures such as return on invested capital help investigate how efficiently a company generates growth.

    Low growth and cyclical earnings can distort the screen. A tiny positive growth denominator produces a very large PEG. A rebound from depressed earnings can produce a striking growth rate that is difficult to sustain. Schwab identifies mature low-growth companies, cyclical businesses, and exceptionally high growth as situations requiring caution.[4]

    Standard PEG also contains no explicit adjustment for dividend yield, debt, or the required return on equity. Those factors can influence the price and earnings already inside the ratio, but dividing by growth does not separately account for them.

    Frequently Asked Questions


    A PEG near one is a common screening benchmark, but there is no universal good PEG. A lower positive value means a lower P/E relative to the growth input. Decide whether that comparison is attractive by examining the forecast, business risk, earnings quality, and investment required to achieve the growth.


    Yes. A negative quotient can result from falling earnings or a negative earnings base in the P/E calculation. It does not represent a bargain under the usual PEG interpretation. Inspect the underlying inputs instead of ranking the negative number against positive PEG values.


    They may use different P/E earnings periods, GAAP or adjusted EPS, growth horizons, estimate providers, or update dates. Read each methodology before comparing the results. Two different PEG values can both follow their stated definitions while answering different questions.


    Either horizon can be used if clearly defined and consistently applied. A one-year rate can be strongly affected by a temporary earnings change. A multiyear annualized forecast looks across a longer period but depends on assumptions further into the future. A five-year cumulative percentage increase must first be annualized.


    It can describe valuation relative to earnings growth, but standard PEG has no dividend-yield term. A mature dividend payer can have a high PEG because its growth denominator is small. Consider its dividend yield, cash generation, and business risk alongside PEG before reaching a valuation conclusion.

    Sources

    Sources consulted October 20, 2026. Company EPS examples cover 2023 and 2024; worked PEG valuations and forecast scenarios are hypothetical.

    1. Fidelity Investments, credited to DST Systems, Inc., Company valuation ratios, Price-to-earnings and Price/earnings-to-growth sections.
    2. Fidelity Investments, Research Glossary: M through R, Price/Earnings Ratio and Price to Earnings Growth Ratio entries.
    3. Aswath Damodaran, NYU Stern, PEG Ratios, definition, fundamental determinants, and propositions.
    4. Will Daniel, Charles Schwab, What Is the PEG Ratio? Basics, Formula, and Risks, June 3, 2026; calculation examples, risks, and FAQs.
    5. Meta Platforms, Inc., 2024 Form 10-K, filed January 30, 2025; Consolidated Statements of Income, page 87, diluted EPS row.
    6. The Coca-Cola Company, 2024 Form 10-K, filed February 20, 2025; Consolidated Statements of Income, page 62, diluted net income per share row.
    7. The Coca-Cola Company, Fourth Quarter and Full-Year 2023 Results, February 13, 2024; full-year EPS discussion.
    8. The Coca-Cola Company, Fourth Quarter and Full Year 2024 Results, February 11, 2025; full-year EPS discussion.
    9. SEC Division of Corporation Finance, Non-GAAP Financial Measures, updated December 13, 2022; Questions 100.01, 100.02, and 100.05.
    Disclaimer

    This article provides general investment education and does not constitute personalized investment advice. Worked PEG values use hypothetical assumptions. Company EPS examples are historical, and future earnings may differ from forecasts. Investment decisions require analysis of the business, valuation assumptions, and your circumstances.

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