Portfolio Beta Calculator
Enter the allocation weight and beta of each holding to get the portfolio's overall beta — a measure of systematic (market) risk relative to the benchmark index.
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Close to market — expected to move roughly in line with the index
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Asset 1 weighted beta
25% ÷ 100% × β1.2 = 0.3 - 2
Asset 2 weighted beta
25% ÷ 100% × β0.8 = 0.2 - 3
Asset 3 weighted beta
20% ÷ 100% × β1.5 = 0.3 - 4
Asset 4 weighted beta
20% ÷ 100% × β0.5 = 0.1 - 5
Asset 5 weighted beta
10% ÷ 100% × β1 = 0.1 - 6
Portfolio beta
0.3 + 0.2 + 0.3 + 0.1 + 0.1 = 1
How does this calculator work?
Portfolio β = Σ (weight_i × beta_i). A beta of 1 means market-like risk; above 1 is aggressive, below 1 is defensive. Enter each holding's portfolio weight (%) and its individual beta — the calculator normalises weights if they don't sum to 100% and shows each asset's beta contribution in a breakdown chart.
Formula
How this is calculated
Beta (β) measures how much an asset tends to move relative to a broad market index such as the S&P 500. A beta of 1.0 means the asset historically tracks the market; a beta of 1.5 means it has moved 50% more than the market on average (more volatile); a beta of 0.5 means it has moved half as much (more defensive). Negative betas (e.g. inverse ETFs or gold in some regimes) move opposite to the market.
A portfolio's overall beta is the weighted average of the individual asset betas, using each holding's portfolio weight as its weight: Portfolio β = Σ (wᵢ × βᵢ). The weights should sum to 1 (100%); if they do not, the calculator normalises them automatically so the result remains meaningful. Each asset's contribution to the total beta equals its weight times its individual beta, shown in the breakdown chart.
Beta is estimated historically (typically from 2–5 years of monthly or weekly return data versus the index) and may change over time; forward beta can differ from historical beta. Beta captures only systematic (market-wide) risk, not idiosyncratic (company-specific) risk. Assets with very short track records, illiquid instruments, or those measured against a different index may have unreliable beta estimates. Values are editable estimates — always source betas from a current financial data provider.
Frequently asked questions
A portfolio beta of 1.3 means that, on average, the portfolio has historically moved 30% more than the benchmark index. If the market rises 10%, the portfolio would be expected to rise about 13%; if the market falls 10%, the portfolio would be expected to fall about 13%. This is sometimes called a high-beta or aggressive portfolio.
Add lower-beta or negatively-correlated assets — for example, government bonds (β often 0.0–0.3), utilities, consumer staples, gold or inverse ETFs. Reducing the weighting of high-beta growth stocks and increasing cash or defensive holdings also lowers overall portfolio beta.
Most financial data providers (Bloomberg, Refinitiv, Yahoo Finance, Morningstar) publish a trailing 5-year monthly beta versus the local index. Betas on different providers may differ because they use different time periods, index benchmarks, or return frequencies. Use a consistent source across all holdings.
Also known as
TG we-Calculate Editorial Team. (2026). Portfolio Beta Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/portfolio-beta-calculator
TG we-Calculate Editorial Team. "Portfolio Beta Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/portfolio-beta-calculator.
TG we-Calculate Editorial Team, "Portfolio Beta Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/portfolio-beta-calculator
@misc{wecalculate_portfolio_beta_calculator, title = {Portfolio Beta Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/portfolio-beta-calculator}}, year = {2026}, note = {TG we-Calculate} }
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