PEG Ratio Calculator
Created by: Emma Collins
Last updated:
Compare a stock’s valuation multiple with its expected earnings growth so a raw P/E can be judged on a more growth-adjusted basis.
PEG Ratio Calculator
FinanceAdd growth context to a stock’s P/E multiple and compare the resulting PEG ratio across alternate growth assumptions.
What is a PEG Ratio Calculator?
A PEG ratio calculator compares a stock’s P/E multiple with its expected earnings-growth rate.
It is a simple way to ask whether a valuation multiple still looks reasonable once growth is considered.
This matters because a higher P/E can be justified when earnings are growing quickly, while a lower P/E can still look expensive if growth is weak or fading.
A useful PEG calculator should therefore make the growth assumption explicit and show how fragile the ratio becomes when that input changes.
How the PEG Calculation Works
The calculator divides the P/E multiple by the expected earnings-growth rate expressed as a whole-number percentage.
That produces a growth-adjusted valuation shortcut rather than a standalone valuation model.
Because forecast growth is uncertain, the output is best used for scenario comparison instead of as a definitive fair-value answer.
Core PEG relationships
PEG ratio = P/E ratio / expected earnings-growth rate
Higher growth at the same P/E → lower PEG ratio
Growth needed for 1.0 PEG ≈ current P/E multiple
Example Scenarios
Example 1: Growth stock comparison
Two stocks with similar P/E ratios can have very different PEG ratios if one is growing much faster.
Example 2: Forecast risk
A small cut to the growth forecast can push PEG much higher and change the valuation story.
Example 3: Sanity check on expectations
Growth needed for a 1.0 PEG helps frame whether the market’s implied growth burden looks realistic.
How People Use This Calculator
- Add growth context to a stock’s P/E multiple.
- Compare growth stocks on a more normalized basis.
- Stress-test a valuation view under different growth assumptions.
- Show how sensitive a growth-adjusted multiple is to forecast changes.
Tips for Better PEG Analysis
Do not treat all growth as equally valuable.
Durable, cash-backed growth deserves more credit than fragile or highly cyclical growth.
A PEG ratio is only as good as the forecast behind it.
If the growth input is overly optimistic, the result will understate valuation risk.
Frequently Asked Questions
What is a PEG ratio?
The PEG ratio compares a stock’s P/E multiple with its earnings-growth rate. It is meant to add growth context to a raw valuation multiple.
Why does growth need to be positive?
The usual PEG formula assumes a positive growth rate. Zero or negative growth makes the ratio far less meaningful as a valuation shortcut.
Does a PEG under 1 guarantee a bargain?
No. It only suggests growth may be high relative to the multiple. Forecast risk, capital intensity, margins, and durability still matter.
Should growth be entered as a percent or decimal?
This calculator expects growth as a percentage number, such as 15 for 15%.
Sources and References
- General stock-valuation references explaining PEG ratios and growth-adjusted multiples.
- Equity-analysis materials discussing forecast sensitivity in PEG-based screening.
Planning Note
PEG Ratio Calculator is a planning estimate. Equity metrics only become useful when the underlying earnings, growth, dividend, and balance-sheet assumptions are credible and comparable.