How this calculator works
Combine holding betas using their shares of portfolio market value. Enter weights as percentage numbers summing to 100, and use betas estimated against the same benchmark and interval. The lists can include cash with an assumed beta of zero. This tool covers fully allocated long-only weights; holding betas themselves may be negative.
Formula
Portfolio beta = sum(weight fraction × holding beta). Convert each percentage weight to a fraction by dividing by 100. The individual contributions add to total portfolio beta.
Worked example
A 60% allocation to beta 1.2 and 40% to beta 0.8 gives beta 1.04. Equal weights in beta -0.5 and beta 1.5 give portfolio beta 0.5.
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Frequently asked questions
Does beta 1 mean perfect correlation?
No. Beta is a slope that also depends on relative volatility. It does not establish perfect correlation or equal total risk.
Can I enter short positions?
Weights here are nonnegative and sum to 100%. A leveraged or long-short portfolio needs an explicit exposure convention outside this tool.
Why must the benchmarks match?
Betas relative to different markets describe different relationships and cannot simply be combined into one benchmark beta.