Beta Coefficient Calculator
Measure a stock's volatility relative to the market.
Enter your values
Enter the stock returns (comma-separated %) you are working with.
Enter the market returns (comma-separated %) you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Beta
- 1.39
- Interpretation
- Significantly more volatile than the market
- Data points used
- 6
Quick answer
A beta above 1 means a stock is more volatile than the market; below 1 means less volatile; negative beta means it tends to move opposite the market.
Beta = Covariance(stock, market) / Variance(market)
At a glance
| What it does | Measure a stock's volatility relative to the market. |
|---|---|
| Category | Investing |
| Inputs needed | Stock returns (comma-separated %), Market returns (comma-separated %) |
| Main output | Beta |
| Formula | Beta = Covariance(stock, market) / Variance(market) |
| Cost | Free — no sign-up, no download |
How to use the Beta Coefficient Calculator
- 1Enter matched period returns for the stock and the market index, in the same order.
- 2The calculator computes covariance and market variance to derive beta.
- 3Use at least 12-24 periods (e.g., months) for a more reliable estimate.
Inputs explained
- Stock returns (comma-separated %)
- Enter the stock returns (comma-separated %) you are working with.
- Market returns (comma-separated %)
- Enter the market returns (comma-separated %) you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Stock returns (comma-separated %)5, -2, 8, 3, -1, 6
- Market returns (comma-separated %)3, -1, 5, 2, -2, 4
Results
- Beta1.39
- InterpretationSignificantly more volatile than the market
- Data points used6
Frequently asked questions
What does beta = 1 mean?
The stock's price tends to move in line with the overall market.
Is beta a good measure of risk?
It captures market-related (systematic) risk only, not company-specific risk, so it's one input among several.
What do I need to enter into the Beta Coefficient Calculator?
Just 2 values: stock returns (comma-separated %), market returns (comma-separated %). Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Beta Coefficient Calculator work out the answer?
A beta above 1 means a stock is more volatile than the market; below 1 means less volatile; negative beta means it tends to move opposite the market. It applies the formula Beta = Covariance(stock, market) / Variance(market) and shows the working so you can check each step by hand.
Is the Beta Coefficient Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.