Sortino Ratio Calculator

Frequently Asked Questions

How is the Sortino ratio different from the Sharpe ratio?

Sharpe divides excess return by total volatility; Sortino divides by downside deviation only. It does not penalise upside swings, so it better reflects risk that investors actually care about.

What is downside deviation?

The standard deviation of returns that fall below a target (often the risk-free rate or zero). Returns above the target are treated as zero deviation.

What is a good Sortino ratio?

Above 1 is generally acceptable, above 2 is good, and above 3 is excellent - but always compare like-for-like over the same period and frequency.

Why annualise it?

Ratios computed from monthly data are scaled by √12 (and the return by 12) so they can be compared with annual benchmarks.

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Investment Disclaimer: Estimates only. Not investment advice.

This calculator provides estimates for educational purposes only and is not investment advice. Past performance does not guarantee future results. Consult with a qualified financial advisor before making investment decisions. All investments carry risk, including potential loss of principal.

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How This Calculator Works

The Sortino ratio measures excess return per unit of harmful volatility. The formula is (R_p − MAR) ÷ σ_d, where R_p is the portfolio return, MAR is your minimum acceptable return (or target), and σ_d is the downside deviation. Downside deviation is computed only from periods that fell below the MAR: for each period we take min(0, r − MAR), square it, average those squares over all periods, then take the square root. Periods above the target contribute zero to the denominator. This is fundamentally different from the Sharpe ratio, which divides by total standard deviation and therefore penalizes large upside swings exactly as much as losses. Because investors do not actually dislike upside surprises, Sortino is often the more economically honest gauge for asymmetric or skewed strategies.

Worked Numeric Example

Suppose a portfolio returns 12% with a MAR of 4%, and periodic returns of 8, −3, 15, −6, 10, 2, −1, 18, 5, −4. Five periods fall below 4 (−3, −6, 2, −1, −4). Their shortfalls from 4 are −7, −10, −2, −5, −8; squared they are 49, 100, 4, 25, 64 summing to 242. Dividing by 10 periods gives 24.2, and √24.2 ≈ 4.92 downside deviation. Excess return is 12 − 4 = 8, so Sortino ≈ 8 ÷ 4.92 ≈ 1.63 - a solid result that a Sharpe ratio would have scored lower because the big +18 and +15 periods would have inflated the denominator.

Real-World Use

Hedge funds, managed-futures programs, and option-writing strategies report Sortino because their return distributions are deliberately asymmetric. A covered-call fund caps upside but keeps premium income; Sharpe unfairly punishes its lack of big up-months, while Sortino rewards its consistency below the target. Pension consultants and fund fact sheets increasingly show Sortino alongside Sharpe so allocators can see whether a manager's volatility is mostly "good" (upside) or "bad" (drawdown) volatility before committing capital. Retirement planners apply the same logic to withdrawal portfolios: a retiree cares far more about the depth and frequency of losing years than about how large the best years were, so the Sortino lens maps directly onto sequence-of-returns risk. When two strategies post the same Sharpe ratio, the one with the higher Sortino is the one whose volatility is concentrated on the upside - usually the more comfortable holding to actually stick with through a full market cycle.

Common Mistakes

Dividing the downside sum of squares by the number of below-target periods instead of the total number of periods - the standard definition uses the full count.

Mixing time frames: the return and the periodic series must share the same horizon, or annualize consistently (×√12 monthly, ×√252 daily).

Confusing the risk-free rate with the MAR. The MAR can be zero, the risk-free rate, or a liability-driven hurdle - pick one and state it.

Reading a single-period Sortino as durable skill; short windows are noisy and a few outliers dominate the downside set.

Annualizing the return but leaving the downside deviation in monthly units (or vice versa), which silently scales the ratio by √12.

Limitations & Related Ratios

Sortino still assumes the past distribution proxies the future and can be gamed by strategies that hide tail risk (selling deep out-of-the-money options shows almost no downside until it does, then shows all of it at once). It is also sensitive to the choice of MAR: shifting the target a few points reshuffles which periods count as "bad" and can move the ratio materially, so always disclose the MAR you used. Because the denominator can be very small when few periods fall below target, a strategy with a short clean track record can post an implausibly high Sortino that will not survive a real drawdown. Pair it with maximum drawdown and the Calmar ratio for a path-risk view, with the Sharpe ratio to see how much of total volatility is upside, and with the Treynor ratio when systematic risk is the relevant lens. This tool is an educational estimate, not investment advice; consult a qualified professional before allocating capital based on any single risk-adjusted metric.

Frequently Asked Questions

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