How to Calculate Capm: Formula, Examples, and Calculator
Clarify definitions, walk through core formulas, and jump to StockCalc's tool for how to calculate capm-without losing track of units or timing.
How to Calculate Capm: Formula, Examples, and Calculator
Updated May 2026 · ~10 min read
CAPM estimates a required return from a selected risk-free rate, beta, and market risk premium. Each input is estimated and depends on currency, horizon, benchmark, return frequency, sample period, leverage, and methodology. CAPM is a model assumption for analysis, not an observed expected return or a forecast guarantee.
When this guide is useful
- Screening and comparisons: you want a repeatable checklist when you rank ideas on how to calculate capm.
- Portfolio reviews: you translate the same definitions each quarter so changes are comparable.
- Thesis checks: you verify a headline or social post with your own numbers before sizing a trade.
The formula
Required return = R_f + β × (E[R_m] − R_f) Beta = covariance(asset, selected market benchmark) ÷ variance(selected market benchmark)
The risk-free rate and market risk premium should use compatible currency and horizon. Historical and forward-looking premium estimates are not interchangeable without explanation.
A conditional CAPM calculation
With Rf = 4%, beta = 1.2, and a selected market risk premium of 5%, CAPM gives 10%. This is a conditional required-return estimate, not the return the security will earn.
Beta is methodology-dependent
- Benchmark, currency, frequency, window, and corporate actions affect beta.
- Thin trading and structural breaks can make historical beta unstable.
- Peer betas require documented unlevering and relevering assumptions.
Model limits
CAPM does not capture every priced risk, liquidity constraint, nonlinear payoff, country exposure, or company-specific scenario. Alternative models may produce different required returns.
Common mistakes
- Using NPV or IRR formulas in place of CAPM.
- Treating beta as a permanent company characteristic.
- Mixing a local-currency risk-free rate with a foreign-currency premium.
- Using a historical market return as a guaranteed future premium.
- Treating the CAPM result as a forecast of realized return.
Try the calculator
Use the interactive calculator to plug in your numbers and see results instantly—without redoing the math by hand.
Open Capm Calculator →FAQ
Which risk-free rate should I use?
Use a rate consistent with the cash-flow currency and horizon; no single government yield fits every analysis.
Which beta should I use?
Document benchmark, window, frequency, leverage treatment, and any adjustment. Different valid methods can produce different betas.
Is CAPM expected return a forecast?
No. It is a model-based required-return estimate under selected assumptions.
Can CAPM be used in emerging markets?
It can be adapted, but currency, sovereign, market segmentation, and country-risk assumptions require explicit treatment.
Continue learning this topic
Move from this guide into a complete calculator path with related tools and glossary terms.
Open the Risk & Portfolio hub →Educational Disclaimer
This article is for educational and informational purposes only and should not be considered investment, financial, tax, or legal advice. Market information may change over time, and readers should verify important details independently before making financial decisions.