Beta Calculator

Use this beta calculator to measure how sensitive a stock is to the market. Enter the covariance and market variance to get beta and gauge volatility.

What it does

The Beta Calculator measures an asset's systematic risk relative to the overall market. It divides the covariance between the asset and the market by the market's variance to produce beta, a single number that describes how sensitive the asset is to market movements.

Data sources & parameters

This calculator uses standard financial formulas and runs entirely in your browser. It needs no external rate data — your result is computed only from the values you enter above.

We always strive to use the latest data for every variable so our results and reports are as accurate as possible. Even so, errors are possible — you should not rely on this tool or its report alone, and we accept no liability for any decision made based on it.

The formula

beta = covariance(asset, market) ÷ variance(market)

How it works

Enter the covariance of the asset with the market and the variance of the market. The tool divides the first by the second. A beta of 1 moves in line with the market, above 1 amplifies market swings, and below 1 dampens them.

Where it is used

Judging how volatile a stock is compared with its benchmark
Feeding beta into the CAPM to estimate an expected return
Building a portfolio with a target overall market sensitivity

Worked example

An asset has a covariance with the market of 0.02 while the market variance is 0.02. Dividing one by the other gives a beta of …, meaning the asset tends to move about 20% more than the market.

What the beta calculator does

Beta measures how sensitive an investment is to moves in the wider market. A high-beta asset tends to exaggerate the market's rises and falls; a low-beta asset moves more gently. Enter the covariance between the asset and the market and the variance of the market, and the beta calculator returns the ratio. It is a starting point for judging risk, comparing holdings and estimating the return an investment should offer.

How beta is calculated

Covariance measures how the asset and the market move together: a large positive covariance means they tend to rise and fall at the same time, a negative one that they move in opposite directions. Variance measures how much the market alone fluctuates around its average.

Dividing covariance by market variance tells you how far the asset tends to move for each unit the market moves. A beta of 1.2 suggests the asset has historically moved about 20% more than the market in the same direction. Both inputs come from historical returns, so beta describes past behavior: a reasonable guide, not a guarantee.

Reading the value

A beta of 1 means the asset has matched the market's volatility, with about the same systematic risk as the benchmark.
Above 1, the asset amplifies the market: a beta of 1.5 implies swings roughly half again as large, raising both potential gains and potential losses.
Below 1, the asset dampens the market: a beta of 0.6 implies smaller swings, typical of defensive sectors such as utilities and consumer staples.
A negative beta means the asset tends to move against the market, which is rare and useful for hedging.

No value is good or bad in itself; the right level depends on how much risk you want and the asset's role in your portfolio.

Why beta matters

The specific risks of a single company, such as a product recall or a change of management, can be reduced by holding many investments. What remains is systematic risk from being exposed to the market at all, and beta measures that part. This is why beta is central to the Capital Asset Pricing Model, in which a higher beta requires a higher expected return to compensate for the extra market risk.

Beta in a portfolio

A portfolio's beta is the position-weighted average of its holdings' betas, so you can estimate it and steer it toward the market sensitivity you want. An investor expecting strong markets might tilt toward higher-beta assets; one expecting turbulence might add lower-beta or negative-beta holdings. Two assets can share a beta yet differ sharply in total volatility, because beta covers only market-related risk, so pair it with standard deviation.

Limits

Because beta comes from past returns, it can change as a company changes, and a beta measured in calm conditions may understate risk in a crisis. Short measurement windows give unstable estimates, while very long ones may mix phases of a company's life that no longer apply. Beta also says nothing about the direction of returns: a high-beta asset is volatile relative to the market, not necessarily a good investment. Use it alongside fundamental analysis and other risk measures, for example to rank holdings by market sensitivity, as an input to CAPM, or to check your portfolio's overall beta against your appetite for risk.

This article is general information only and is not financial advice.

About This Beta Calculator

Use this beta calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.

Frequently asked questions

How does the beta calculator work?

The calculator divides the covariance between an asset's returns and the market's returns by the variance of the market. The result is beta, a single number showing how strongly the asset tends to move when the market moves. You enter the two statistics and the tool returns the ratio.

What does a beta of 1 mean?

A beta of 1 means the asset has historically moved in line with the market. If the market rises or falls by a given amount, an asset with a beta of 1 has tended to move by roughly the same amount, so it carries about the same systematic risk as the benchmark.

What is a high or low beta?

A beta above 1 means the asset has been more volatile than the market, amplifying its swings. A beta below 1 means it has been less volatile, dampening market moves. A negative beta means the asset has tended to move in the opposite direction to the market.

Where do covariance and market variance come from?

Both are calculated from historical returns measured over the same period and frequency, such as monthly returns over five years. Covariance captures how the asset and market move together, while variance captures how much the market alone fluctuates.

Can beta be negative?

Yes. A negative beta occurs when an asset tends to rise while the market falls and vice versa. Some hedging assets and inverse instruments show negative beta, which can reduce the overall volatility of a diversified portfolio.

Is my data kept private?

Yes. The calculation runs entirely in your browser. Nothing you enter is uploaded, stored, or shared with anyone.

About the author

Written and reviewed by

Taha Kheirandish

Economics student and independent researcher

Taha Kheirandish reads tax codes the way other people read maps — to find out where a system actually leads, not where it claims to go.

He is an economics student, and his work here is comparative by design. A pension deferral bonus in Quebec, a commuting allowance in Germany, a rent-increase ceiling in the Netherlands: each is a decision a government made about how money should move, and each reads differently once you set it beside eight others. He builds and checks these calculators across nine markets from primary sources — the regulation rather than a summary of it, the ministry’s own circular rather than a news item quoting it.

That is the editorial standard of the site as well as his habit. Every rate, threshold and bracket here carries the document it was read from and the date it takes effect, and gets re-checked when the law moves rather than when someone happens to notice.

He is a researcher, not a licensed adviser, and nothing on this site is personal financial advice. It is arithmetic done carefully with its sources shown — so that you can check it, and take it to someone who is.

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