How the Treynor Ratio Calculator works
The Treynor Ratio, developed by Jack Treynor, measures how much excess return a portfolio earned for each unit of market (systematic) risk it took on, where risk is measured by beta rather than total volatility. It answers a narrower question than the Sharpe Ratio: not "how much return per unit of total risk," but "how much return per unit of exposure to the overall market."
The formula
For a portfolio return Rp, a risk-free rate Rf, and a portfolio beta β, the Treynor Ratio is:
Treynor Ratio = (Rp − Rf) / β
The numerator, Rp − Rf, is the excess return: the return earned above a risk-free benchmark such as a short-term Treasury bill. Dividing by beta expresses that excess return per unit of market risk instead of as a raw percentage, which makes portfolios with different market exposure comparable on the same footing.
Worked example
Take a portfolio that returned 12% over the period, a risk-free rate of 4%, and a portfolio beta of 1.2. The excess return is 12% − 4% = 8%, and the Treynor Ratio is 8% / 1.2 ≈ 6.67. A second portfolio with the same 8% excess return but a beta of 0.8 would score 8% / 0.8 = 10.0 — a higher Treynor Ratio, because it earned the same excess return while carrying less market risk.
Treynor Ratio versus CAPM alpha
This calculator also reports the Capital Asset Pricing Model (CAPM) expected return, Rf + β × (market return − Rf), and Jensen's alpha, the portfolio's actual return minus that CAPM expectation. Alpha is a companion figure: it shows return earned above what CAPM predicted for that level of beta, in percentage-point terms rather than as a per-unit-of-risk ratio.
What moves the ratio most
- Beta: because beta sits in the denominator, a low or near-zero beta amplifies the ratio dramatically — even a small excess return can produce a very large or unstable Treynor Ratio when beta is close to zero.
- Excess return: a higher portfolio return relative to the risk-free rate directly raises the ratio, holding beta constant.
- Sign of beta: a negative beta (a portfolio that tends to move opposite the market) flips the sign of the ratio, so a negative Treynor Ratio can mean either underperformance or a negative-beta portfolio with positive excess return — always check beta's sign before interpreting the number.
Limits of the Treynor Ratio
Treynor assumes the portfolio is well-diversified enough that beta captures most of its relevant risk. For a concentrated or undiversified portfolio, unsystematic (stock-specific) risk can be substantial but invisible to this ratio — the Sharpe Ratio, which divides by standard deviation instead of beta, is usually the better tool in that case. The ratio also depends on the accuracy of the beta estimate used, which itself is sensitive to the time period and benchmark chosen. This calculator performs the arithmetic only; it is not personalized investment advice.