Sharpe Ratio Calculator: Measure Your Risk-Adjusted Return

The Sharpe ratio measures how much return your strategy generates for every unit of risk it takes on, calculated as excess return divided by standard deviation; a ratio above 1.0 is decent, above 2.0 is strong, and below 0.5 usually signals a strategy that's riskier than its returns justify.

Most trading journals, including TradeZella and TradesViz, calculate this number automatically, but knowing the formula matters because it tells you what the number actually rewards: consistency, not just raw gains. Walk through the math once by hand using your own trade history, and the number on your dashboard stops being an abstract score and starts telling you something specific about how your strategy behaves.

What is a good Sharpe ratio for a trading strategy?

A Sharpe ratio between 1.0 and 2.0 is considered good for an individual trader or retail strategy in 2026, meaning your returns comfortably outpace the volatility you took on to earn them. Professional funds typically target 2.0 or higher, and anything under 0.5 usually means the risk isn't being paid for.

The risk free rate you plug into the formula matters more than most traders assume. As of August 25, 2026, the 3 month Treasury bill yield sits at 3.80 percent, down from roughly 4.19 percent a year earlier. Use whatever the current 3 month T bill rate is when you run the math yourself, since a stale number from a prior year will distort your real Sharpe ratio, especially in a shifting rate environment.

With the 3 month T bill yield at 3.80 percent as of August 25, 2026, a strategy needs roughly 3.8 percent in annualized return before its Sharpe ratio even turns positive.

How do you calculate the Sharpe ratio step by step?

Most traders skip straight to a calculator, and that's fine once you understand what's happening under the hood. Plug your own returns into the calculator on this page and it runs steps 2 through 5 automatically; you only need to handle step 1, pulling your own numbers together.

Annualizing monthly data means multiplying by the square root of 12, or about 3.46, which is the single step traders most often get wrong when calculating Sharpe ratio by hand.

What inputs do you need for the Sharpe ratio formula?

• A return series: at least 12 monthly data points, or 20+ trades if you're measuring a trading strategy rather than a portfolio
• The current risk free rate, typically the 3 month Treasury bill yield, 3.80 percent as of August 2026
• Your returns expressed as percentages, not dollar amounts, so the standard deviation calculation stays consistent
• A consistent time period across every data point; don't mix weekly and monthly returns in the same calculation
• Optional: a benchmark return like the S&P 500's if you want to compare your Sharpe ratio against buy and hold

The biggest input error shows up when traders mix time periods, like averaging six months of daily returns with six months of weekly ones. That single mistake can swing a reported Sharpe ratio by 0.3 or more, enough to make a mediocre strategy look great or a solid one look weak.

Most brokers, including Interactive Brokers and TD Ameritrade's thinkorswim, let you export monthly account values as a CSV, which is the fastest way to build a clean return series without retyping numbers. Trading journal apps like TradesViz pull this data automatically if you connect your broker instead of uploading statements by hand.

Using at least 20 trades or 12 months of returns keeps a Sharpe ratio calculation statistically meaningful; anything shorter is more noise than signal.

Sharpe ratio vs Sortino ratio: what's the difference?

If your equity curve has occasional huge up months, like a swing strategy that catches a few large trend trades a year, the Sharpe ratio can understate how good the strategy actually is because it treats big gains as risk the same as big losses. The Sortino ratio fixes that by only counting downside deviation. Most professional performance reports show both numbers side by side for exactly this reason.

Going back to the 0.65 Sharpe ratio example above, if that same strategy's downside deviation was only 12 percent instead of the full 22 percent standard deviation, the Sortino ratio would come out to 14.20 divided by 12, or about 1.18, nearly double the Sharpe number. That gap tells you most of the strategy's swings came from unusually good months, not bad ones.

A strategy can post a mediocre 0.8 Sharpe ratio and a strong 1.6 Sortino ratio at the same time, and that gap usually means the strategy's volatility comes mostly from upside months, not losing streaks.

What are the limits of the Sharpe ratio?

The ratio also assumes returns are roughly normally distributed, which real trading returns rarely are. Strategies with a small number of large winners, common in trend following, will show a Sharpe ratio that undersells them, while strategies that collect small consistent gains and occasionally take a large loss, common in options selling, will show a Sharpe ratio that oversells them right up until the large loss happens.

This is also why a single blowup month can retroactively make years of a great looking Sharpe ratio meaningless. A strategy that posted a 1.8 Sharpe ratio for three straight years and then lost 40 percent in one month, the pattern behind several option selling funds that failed in past volatility spikes, was never really a 1.8 strategy. The ratio just hadn't seen its tail risk yet.

A Sharpe ratio calculated on fewer than 20 trades or 12 months of data tells you almost nothing about whether a strategy will hold up over the next year.

The verdict

The Sharpe ratio is a fast, standardized way to check whether your returns justify the risk you're taking, and a result between 1.0 and 2.0 is a reasonable target for most retail traders and investors working through 2026. It won't tell you everything: pair it with max drawdown and, if your strategy has lumpy winning months, the Sortino ratio too. Use at least 12 months of returns and the current risk free rate, 3.80 percent as of August 25, 2026, and you'll have a real number to compare against your past performance or against a buy and hold benchmark like the S&P 500. Recalculate it quarterly rather than checking it daily, since short windows swing the number around more than they should. The traders who get the most out of this metric treat it as one input among several, not a single score that decides whether a strategy is good or bad.

A Sharpe ratio recalculated quarterly with at least 12 months of trailing data is a far more reliable signal than the same ratio checked daily off a handful of recent trades.