What Is a Good Sharpe Ratio for a Trading Strategy?

People love the Sharpe ratio because it collapses a messy question how good is this strategy? into a single tidy number. That tidiness is also its danger. The Sharpe ratio answers a narrow question well, and a high one can be genuinely meaningful or completely manufactured. Knowing which is the whole skill.

What the Sharpe ratio actually measures

The Sharpe ratio, developed by Nobel laureate William Sharpe, divides a strategy's return above the risk-free rate by the volatility of its returns. In plain terms: it asks how much reward you got for how bumpy the ride was. A strategy that makes 10% with gentle swings has a higher Sharpe than one that makes 10% with stomach-churning lurches because it delivered the same reward with less risk.

The key insight is that return alone is a bad measure of quality. Two strategies can earn the same amount while taking wildly different risks. The Sharpe ratio is an attempt to put them on equal footing by penalizing volatility.

What counts as good

There is no official threshold, but rough conventions exist. A Sharpe below 1 is generally considered weak; around 1 is respectable; 2 is strong; and 3 or higher is exceptional and, in a backtest run by an individual on limited data, often a red flag rather than a trophy. Professional funds frequently operate with long-run Sharpe ratios closer to 1, which should calibrate your expectations: if your homemade backtest shows a Sharpe of 4, the most likely explanation is not genius but overfitting.

Context matters too. Sharpe depends on the time period measured and the frequency of returns, and it can look very different across calm and volatile markets. A single number stripped of that context can mislead.

Why a high Sharpe is easy to fake

A backtest Sharpe is only as honest as the test behind it. Ignore fees and slippage, and the ratio rises artificially. Tune the rules until they fit past noise, and the ratio rises further. Run the test on too short a window, and a lucky streak can produce a dazzling Sharpe that means nothing. The SEC's repeated warning that past performance does not predict future results applies directly: a high historical Sharpe is a description of the past, not a forecast.

The Sharpe ratio also has a known blind spot. It treats upside and downside volatility the same, penalizing big gains as if they were risk. Some traders prefer related measures that focus only on downside but no single ratio escapes the deeper problem that a number computed on flattering assumptions is a flattering number.

How to use it honestly

Treat the Sharpe ratio as one lens among several, not a verdict. Confirm the backtest charged realistic costs. Make sure it covers enough data and varied conditions, not one easy stretch. Check whether the Sharpe holds on data the strategy was never tuned on the out-of-sample test that overfit ratios fail. And read it alongside drawdown and trade count, because a great Sharpe built on ten trades is not a great strategy.

Used this way, the Sharpe ratio is a useful sanity check: it can quickly flag a strategy that took too much risk for its reward. What it cannot do is promise that a good past number will repeat. The most useful instinct is to be more skeptical of a high Sharpe than impressed by it and to let honest testing, not a single statistic, drive the decision.

TRION computes the Sharpe ratio from backtests on real stored historical data with realistic costs, and presents it next to drawdown and trade count so you never read it in isolation. If the ratio cannot be computed honestly, TRION shows N/A.

TRION does not place real orders or promise that a strong past Sharpe will repeat. It exists to give you an honest reading of risk versus reward, and to leave the decision with you.