Calculator
Alpha & Beta Calculator
Alpha & Beta Calculator
Beta (Market Sensitivity)
1.25
Avg Portfolio Return
12.46%
Avg Benchmark Return
11.48%
Risk & Reward Analysis
With a beta of 1.25, your portfolio carries more market risk than the benchmark. Alpha of -0.77 percentage points is close to zero, meaning returns were approximately what the CAPM model says you deserved for that risk — the result is mostly market exposure, for better or worse.
Alpha and beta are backward-looking statistics based on the returns you enter. Past risk and return patterns are not guarantees of future behaviour, and a short sample window can flatter or punish a strategy unfairly.
Alpha & Beta: Separating Skill from Market Exposure
When an investment does well, investors deserve to know why: was it genuine manager skill, or simply riding a rising market? Alpha and beta are the two classic statistics that answer that question. Beta measures market sensitivity — how much a portfolio tends to move for every point the benchmark moves. A beta of 1.2 means the portfolio historically swings 20% harder than the market in both directions; a beta of 0.6 means it swings roughly 40% less. Alpha then measures what is left over: the average annual return the portfolio earned above (or below) the fair return implied by its beta, according to the Capital Asset Pricing Model (CAPM). For Australian investors these metrics cut straight to practical decisions. An expensive active fund that returns 12% while the ASX 200 returns 13% looks like an underperformer at a glance — but if it did so at a beta of 0.75, it actually earned positive alpha, delivering more return per unit of market risk than the index itself. Conversely, a portfolio that beats the index with a beta of 1.4 has not beaten the market at all; it merely amplified it. Running your own annual returns against the benchmark you actually compare yourself to — the ASX 200 for large Australian share exposure, a global blend for an international fund — converts vague performance feelings into an honest audit of whether you are being paid for the risk you take.
Behind the Formula: Regression on Market Returns
Beta is computed from the covariance between your portfolio's returns and the benchmark's returns, divided by the variance of the benchmark's returns: Beta = Cov(Rp, Rb) / Var(Rb). Covariance captures how the two series move together — if your returns are consistently higher in the years the market is up and lower when it falls, covariance is positive and beta is positive. Because variance is always positive, beta's sign and size come entirely from how strongly your portfolio tracks the market. Alpha plugs beta into the CAPM expected-return equation: Expected Return = Risk-Free Rate + Beta x (Benchmark Return − Risk-Free Rate), and then subtracts that expectation from your portfolio's average actual return. A positive alpha means the portfolio earned more than its market exposure justified; a negative alpha means the opposite. The tool also reports the correlation coefficient and R-squared (correlation squared): R-squared near 1 means the benchmark explains nearly all of your results and the alpha reading is highly reliable, while R-squared below about 0.5 means much of your performance is driven by factors the benchmark does not capture, so alpha should be read with caution. All statistics use sample (n−1) variance so short multi-year samples stay unbiased. For Australian inputs, a sensible risk-free rate is the 10-year Australian Government bond yield or the bank bill rate, and franking credits should be included when they are part of the returns you compare.
Expert Insights
Compare Yourself to the Benchmark You Actually Own
Alpha is only meaningful against the right yardstick. An Australian small-cap portfolio benchmarked against the ASX 200 can show large false alpha simply because small caps had a good run, and a portfolio half in global shares benchmarked against the ASX will look artificially uncorrelated. Match the benchmark to the portfolio's real style — ASX 200 for large Australian holdings, a 60/40 blend for a balanced super account, an aggregate bond index for fixed income. Mis-benchmarking flatters bad strategies and punishes good ones.
High Beta Is Not Alpha — It Is Leverage in Disguise
Many retail portfolios that 'beat the market' during rallies are concentrated in high-beta names or geared ETFs. CAPM strips that out: a beta-1.5 portfolio that returned 20% when the market returned 15% with a 4% risk-free rate produced negative alpha, because 15% + 0.5 x 11% = 20.5% was the fair return for that risk. You can replicate high beta cheaply with modest gearing — you cannot replicate genuine skill.
Use R-Squared to Judge How Seriously to Take the Alpha
A low R-squared means the benchmark barely explains your returns, so alpha is dominated by idiosyncratic bets and measurement noise. Professional analysts generally consider alpha reliable only when R-squared is above 0.5–0.6. If your alpha looks fantastic but R-squared is 0.2, the result is mostly about what the benchmark failed to capture — such as international exposure, franking, or commodities — not about skill or failure.
Actionable Tips
- 1
Audit Your Fund's Alpha Before Renewing Your Faith in It
Pull five years of annual total returns for any actively managed fund you own and a matching index, plug them into this tool, and check alpha. If alpha is negative after fees, you are paying a premium MER for under-delivered risk-adjusted performance — a strong signal to consider a low-cost index alternative in your super or trading account.
- 2
Check Your Portfolio's Beta Before a Correction, Not After
If your beta is above 1.2, a routine 20% market correction implies a 25%+ drawdown for you. Decide now whether you could emotionally tolerate that and act if not — rebalancing beta downward with bonds or low-volatility funds is far cheaper than panic-selling at the bottom.
- 3
Re-run the Analysis with Monthly Data When Possible
Five annual data points produce only five observations, which makes alpha and beta estimates noisy. If your broker or fund platform exports monthly total returns, use 36–60 monthly observations for much tighter statistics. Annual returns are serviceable for a rough read; monthly data is what professionals use.
Real-World Examples
Kevin Learns His Stock Picks Had No Alpha
Kevin, a marketing manager in Melbourne, averaged 16% annually over five years and bragged about beating the ASX 200's 14%. Running both series through the calculator revealed a beta of 1.3 and an expected return of 16.3% for that risk — his actual alpha was slightly negative. His returns were pure amplified market exposure, and a plain index fund with zero stock-picking would have delivered similar results at none of the effort.
Sandra's Boring Portfolio Had Real Alpha
Sandra, a retired teacher from Adelaide, held a conservative mix of franking dividend shares and bonds that returned 9% against the market's 12%, and she assumed she was behind. The tool showed a beta of just 0.55: her CAPM-expected return was only 7.3%, giving her a positive alpha of 1.7 points per year. Her portfolio had genuinely outperformed on a risk-adjusted basis — she had been judging a shield by the standards of a sword.
The Chen Family Vets Their Fund Adviser
The Chens' financial adviser charged 1.25% annually and had returned 11.5% per year over five years versus a 60/40 benchmark's 10.8%. Alpha analysis showed a beta of 1.05 and a CAPM-expected return of 11.4% — alpha was effectively zero before fees and negative after. They moved the account to low-cost index funds inside super, saving roughly 1% per year in fees while keeping the same market exposure their returns were actually reflecting.
Glossary of Terms
- Beta
- A measure of an investment's sensitivity to benchmark market movements. A beta of 1 tracks the market, above 1 amplifies swings, below 1 dampens them.
- Alpha
- The average annual return earned above or below the return that CAPM predicts for the portfolio's level of market risk — the statistic closest to 'skill'.
- R-Squared
- The share of a portfolio's return variance explained by the benchmark, from 0 to 1. Higher R-squared means alpha and beta readings are more trustworthy.
Frequently Asked Questions
Everything you need to know about this topic.
Ivy Sinclair-Wren
Financial Chaos Analyst
Ivy Sinclair-Wren is a Financial Chaos Analyst covering investing, AI, wealth psychology, and the emotional consequences of opening finance apps during market crashes. Based in Melbourne, she specializes in demystifying the Australian tax code and helping users navigate the intersection of spreadsheet logic and human irrationality.