CAPM Calculator
Use the capital asset pricing model to estimate the return investors should require from a stock or portfolio given its beta. Enter the risk-free rate, beta and either the expected market return or the market risk premium, and compare with an actual or forecast return to get alpha.
For Jensen's alpha.
How to use the CAPM Calculator
- Enter the risk-free rate, usually the yield on a government bond matching your time horizon.
- Enter the beta of the stock or portfolio (1 = moves with the market).
- Enter the expected market return, or switch to entering the market risk premium.
- Optionally add an actual or forecast return to see Jensen's alpha.
- Read the expected return and check the security market line and beta table.
CAPM formula
E(R) = Rf + β × (Rm − Rf)
- E(R): expected (required) return on the asset, also used as the cost of equity
- Rf: risk-free rate, such as a government bond yield
- β: beta, the asset's sensitivity to market movements
- Rm − Rf: market risk premium, the extra return expected from the market over the risk-free rate
Example: risk-free rate 4%, beta 1.3, expected market return 9%. Market risk premium = 9% − 4% = 5%. Expected return = 4% + 1.3 × 5% = 10.5%. If the stock actually returned 12%, Jensen's alpha = 12% − 10.5% = +1.5 points.
Expected return by beta
With a 4% risk-free rate and a 5% market risk premium:
| Beta | Typical description | Expected return |
|---|---|---|
| 0 | No market risk (like a treasury bill) | 4.0% |
| 0.5 | Defensive: moves about half as much as the market | 6.5% |
| 1.0 | Moves with the market (an index fund) | 9.0% |
| 1.5 | Aggressive: moves about 50% more than the market | 11.5% |
| 2.0 | Highly sensitive to the market | 14.0% |
The line through these points is the security market line. Assets plotting above it offer more return than CAPM requires for their beta (positive alpha); those below offer less. CAPM's inputs are estimates, so small changes in the risk premium or beta can move the result noticeably.
Frequently asked questions
What is the CAPM formula?
Expected return = Rf + β × (Rm − Rf), where Rf is the risk-free rate, β the asset's beta and Rm the expected return on the market. The term (Rm − Rf) is the market risk premium. With Rf = 4%, β = 1.3 and Rm = 9%, expected return = 4% + 1.3 × 5% = 10.5%.
What does beta mean?
Beta measures how much an asset's returns move with the overall market. A beta of 1 moves in line with the market, 1.5 tends to move 50% more, 0.5 half as much, and a negative beta tends to move the opposite way. Beta is usually estimated from several years of past returns against an index.
What risk-free rate should I use?
Use the yield on a government bond in the same currency as the cash flows, typically a 10-year treasury yield for long-term valuations or a 3-month bill for short horizons. Keep the same choice for the market return or risk premium.
What is the market risk premium?
It is the extra return investors expect from the stock market over the risk-free rate, Rm − Rf. Estimates used in practice commonly fall in the 4% to 7% range, depending on the method and the period studied. If you already have a premium estimate, choose the market risk premium option and enter it directly.
What is Jensen's alpha?
Alpha = actual return − CAPM expected return. If a fund returned 12% while its CAPM expected return was 10.5%, its alpha is +1.5 percentage points: it beat what its market risk alone would predict. Negative alpha means it lagged.
How is CAPM used in valuation?
CAPM's expected return is the most common estimate of a company's cost of equity. That cost of equity feeds into WACC, which is the discount rate in a discounted cash flow valuation. Use the WACC calculator for the next step.
What are the limitations of CAPM?
CAPM assumes beta is the only risk that matters and that past beta predicts future risk. In practice returns also relate to factors like company size and value, betas change over time, and the market return and risk premium are estimates. Treat the result as a reasonable starting point, not a precise forecast.