CAPM Calculator

Calculate the required rate of return for an asset using the Capital Asset Pricing Model.

Status: Algorithmic Audit (CPA Review Pending)
Jurisdiction: United States (IRS & SSA Standards)
Tax Year / Constants: 2026 Statutory Limits
Data Privacy: 100% Client-Side In-Browser

The Mathematical Formula

Expected Return E(R_i) = R_f + β_i × [ E(R_m) - R_f ]

Variable & Parameter Definitions

  • E(R_i) Required or expected rate of return for individual stock or asset i.
  • R_f The risk-free rate of return (yield on US Treasury 10-Year or 3-Month Bills).
  • β_i (Beta) Measure of asset systematic non-diversifiable volatility relative to the overall market (Beta = 1.0 matches market).
  • E(R_m) - R_f Equity Market Risk Premium (ERP): the excess return demanded by investors to hold risky equities over risk-free Treasuries.

Real-World Worked Scenario: Calculating Cost of Equity for a Tech Stock (Beta = 1.35)

An analyst calculates the required return for a technology firm with a Beta of 1.35. The US 10-Year Treasury risk-free rate is 4.25% and expected market return is 9.50%.

  1. Market Risk Premium (ERP): 9.50% - 4.25% = 5.25%.
  2. Systematic Risk Adjustment: Beta 1.35 × 5.25% = 7.0875%.
  3. Required Return (E(R_i)): 4.25% (Risk-Free) + 7.0875% (Risk Premium) = 11.34%.
  4. Application: The firm cost of equity is 11.34%, which serves as the discount rate hurdle for capital investments and DCF equity valuation.
Key Financial Takeaway: Higher beta stocks must deliver higher expected returns to compensate investors for bearing greater non-diversifiable systematic market risk.

Strategic Insights & Pitfalls to Avoid

  • ✓ Beta Interpretation: Beta < 1.0 (defensive utilities/consumer goods) indicates lower volatility than the market; Beta > 1.0 (tech/biotech) indicates higher volatility.
  • ✓ Unsystematic Risk Diversification: CAPM assumes unsystematic company-specific risk can be eliminated entirely through holding a diversified portfolio of 25–30 stocks.
  • ✓ WACC Integration: Cost of Equity derived from CAPM is a mandatory direct input into the Weighted Average Cost of Capital (WACC).

Frequently Asked Questions

What does a Beta of 1.5 mean?

If the overall market gains or drops by 10%, a stock with a Beta of 1.5 is expected on average to move by 15% in the same direction.

What benchmark is used for the risk-free rate in CAPM?

For US equities, institutional analysts standardly use the current yield on the 10-Year US Treasury note.

What is a typical equity market risk premium?

Historically, the US equity market risk premium has averaged between 4.5% and 6.0% above Treasury yields over long periods.

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