Risk/Reward Ratio, Explained: The Break-Even Math, What 76 Years of S&P 500 Data Say About Two to One, and What Traders Actually Set

The risk/reward ratio compares what a trade can lose if it hits your stop with what it can make if it hits your target. Buy a stock at $100 with a stop at $97 and a target at $106, and you are risking $3 to make $6: a ratio of 1:2, usually said as "two to one." The ratio matters because it sets the win rate you need to break even. At two to one you can be wrong on two trades out of three and still not lose money, before costs. At one to two you have to be right two times out of three.

That arithmetic is where most guides stop, and it is also where the trouble starts, because a wider target and a tighter stop are not free. The tighter stop gets hit more often, so the ratio you set and the win rate you get are tied together. This guide covers the math, then puts numbers on the trade-off using 76 years of S&P 500 daily prices, then shows what target and stop pairs real automated accounts actually set, and ends with how to choose a ratio for your own trading.

The break-even math

Call the ratio R, the reward per unit of risk. The break-even win rate is 1 divided by (1 + R). Your edge per trade, called expectancy, is the win rate times the average win, minus the loss rate times the average loss.

• R = 0.5 (risk $2 to make $1): break-even win rate 66.7%.
• R = 1 (risk $1 to make $1): break-even win rate 50%.
• R = 1.5: break-even win rate 40%.
• R = 2 (risk $1 to make $2): break-even win rate 33.3%.
• R = 3: break-even win rate 25%.

Worked example: 100 trades, each risking $100. At two to one with a 45% win rate, 45 wins make $9,000 and 55 losses cost $5,500, so you net $3,500, or $35 a trade. At one to one with the same 45% win rate, you net minus $1,000. At one to one you need 50% just to tread water, and after commissions and slippage a little more. This is why every risk-management guide, including ours, tells you to aim for at least two to one.

The catch: the ratio and the win rate are not independent

Here is the part the formula hides. A tight stop is hit by ordinary noise. A far target is reached less often and takes longer. So when you move from one to one to two to one by tightening the stop, your win rate falls, and the question is whether it falls by more or less than the math gained you.

We measured this on the S&P 500 itself, using every daily close from January 3, 1950 through October 9, 2026 from Yahoo Finance, 19,285 entry days in all. For each day we asked: in the next 30 trading days, which does the index reach first, a target above the entry or a stop below it? Closes only, so a stop that would have been touched intraday but not at the close does not count, which flatters the stop slightly. Price only, no dividends, no costs. The results for a few common pairings:

• Target +6%, stop -3% (two to one): the stop was hit first on 37.6% of entry days and the target first on 17.2%; 45% of the time neither was reached in 30 days. The stop was hit more than twice as often as the target.
• Target +3%, stop -3% (one to one): target first 47.3%, stop first 34.4%, neither 18.2%. Equal distances, but the target wins more often because the index drifts upward.
• Target +2%, stop -1% (two to one, tight): stop first 55.0%, target first 43.7%. Almost every entry resolved within the month, and the one-percent stop lost the race more often than not. Median time to the stop: four trading days.
• Target +6%, stop -10% (a stop wider than the target): target first 19.0%, stop first 4.7%, neither 76.3%. The wide stop was almost never hit, and most trades simply expired unresolved.
• Target +10%, stop -5%: target first 3.7%, stop first 20.2%. A ten-percent move in a month is rare for the index, so the two-to-one ratio delivered a win rate far below its 33% break-even on first-touch outcomes alone.

Now add the unresolved trades back in at whatever the index was worth on day 30, and compute the average outcome per entry. Since 1950: +6/-10 averaged 0.91% per entry, +6/-6 averaged 0.91%, +6/-3 averaged 0.82%, +10/-5 averaged 1.04%, +4/-2 averaged 0.61%, +3/-3 averaged 0.47% and +2/-1 averaged 0.34%. Since 2000 the ordering is the same and every number is a little lower. The spread between the best and worst configuration is small, and nearly all of it is the market's own upward drift over a month showing up in whichever configuration stayed in the trade longest.

The lesson is not that two to one is wrong. It is that the ratio does not create an edge by itself. On an asset with no edge beyond drift, every ratio converges on roughly the same expectancy, and the tight-stop versions get there with more losing trades and more trading. A ratio only pays when the entry has a real edge and the stop sits beyond the noise, far enough that it is hit because the idea failed, not because the stock wiggled. Where to place that stop is the decision; the ratio is what falls out of it.

What traders actually set

We can see the target and stop percentages JorgAI members set for their automated accounts, which is a rare look at the ratios real traders choose rather than the ones they say they use. Of the accounts with both a profit target and a stop-loss configured (27 at the time of writing), the median ratio is 1.2 to one. Nine of the 27 have a stop wider than their target, a ratio below one. Seven sit between one and 1.5, two between 1.5 and two, and nine are at two to one or better. The most common pairing in the settings table is a 6% target with a 10% stop, a ratio of 0.6. That is also what a new JorgAI account starts with, a deliberately wide stop so that volatile names are not stopped out by noise, so part of that count is accounts that kept the default; from the S&P data above it is the configuration that is almost never stopped out and mostly rides the market. Twenty-three of 48 accounts with any exit set also use a trailing stop, which turns a fixed ratio into a moving one.

The exit records show the third variable the ratio ignores: time. Across automated trades that have closed, the median hold for a trade that reached its profit target was 3.6 hours. For a trade that hit its stop it was 2.0 hours, and for a trailing-stop exit 3.6 hours. Trades that reached neither and were closed by the stale-position rule had a median hold of 67 hours, nearly three trading days. Winners and losers resolve in hours; the trades that do neither sit for days with capital tied up. A time stop, closing anything that has not moved in a set period, is the piece of the ratio nobody writes down.

How to choose a ratio for your own trading

• Start from the stop, not the target. Set the stop where the trade idea is wrong: below the level you bought against, or at one to two times the stock's average daily range. Then see what target is realistic within your holding period, and let the ratio fall out. Setting a target first and squeezing the stop to make the ratio look good is the mistake the S&P numbers above punish.
• Measure your real win rate at that stop distance. Thirty trades is the minimum. If a two-to-one plan produces a 30% win rate, it loses money. If a 1.5-to-one plan produces 50%, it makes money. The plan that survives is the one whose ratio and measured win rate clear break-even with room to spare, not the one with the prettier ratio.
• Size the position from the stop distance. Risk per trade divided by the distance to the stop gives the share count. A 3% stop on a $10,000 account risking 1% means a $3,333 position; a 10% stop means a $1,000 position. Position sizing is how the ratio becomes dollars.
• Add a time stop. If a trade has not moved toward the target in a set number of days, close it. The capital is worth more in the next idea than in a trade that is doing nothing.
• Measure the realized ratio, not the planned one. Slippage on the stop, early profit-taking and moved stops all shrink the ratio you actually get. A planned two to one that is routinely taken off at half the target is a one to one in practice, and it needs a 50% win rate, not 33%.

Do not move the stop. The ratio only means something if the stop is where you said it was. Moving it down to "give the trade room" is the behavior that turns small losses into large ones, and it is the single most common way traders turn a positive-expectancy plan into a losing one.

If you want targets, stops, trailing stops and a time stop applied the same way on every trade, without being tempted to move them, that is what JorgAI does inside the brokerage account you already have. You set the percentages once and it enforces them.

Quick answers

What is a good risk/reward ratio? Two to one is the common target: risk $1 to make $2, which breaks even at a 33% win rate. But the ratio is only good if your measured win rate at that stop distance clears the break-even with room to spare. A one-to-one plan with a 55% win rate beats a two-to-one plan with a 30% win rate.

How do you calculate the risk/reward ratio? Divide the distance from entry to target by the distance from entry to stop. Entry $100, stop $97, target $106: reward $6 divided by risk $3 equals 2, written 1:2 or "two to one."

What win rate do I need at two to one? 33.3% to break even before costs; aim for 40% or better to cover commissions and slippage.

Why does my stop get hit so often with a two-to-one ratio? Because tightening the stop to improve the ratio puts it inside normal price noise. On the S&P 500 since 1950, a 3% stop paired with a 6% target was hit first on 38% of entry days versus 17% for the target. The fix is a stop set by volatility or structure, with the target derived from it, not the other way around.

Is a risk/reward ratio below one ever right? It can be, for high-win-rate strategies such as mean reversion in a trending market. In our S&P test, a 6% target with a 10% stop was stopped out on under 5% of entry days and averaged about the same per-trade outcome as two to one. The cost is that each losing trade is large, so position size has to be smaller.

What is the difference between risk/reward and expectancy? The ratio describes one trade's plan. Expectancy is the average result across many trades: win rate times average win minus loss rate times average loss. The ratio is an input; expectancy is the output, and it is the number that decides whether a strategy makes money.

Data: S&P 500 daily closes January 3, 1950 through October 9, 2026 from Yahoo Finance (ticker ^GSPC); first-touch and average-outcome figures are our own computation on that series, price only, closes only, 30-trading-day horizon with overlapping windows, excluding dividends and costs. Settings and exit-timing figures come from JorgAI members' account settings and closed trades through October 12, 2026 and describe configuration and mechanics only, not returns. Stop-loss definition per Investor.gov. This article is education, not investment advice.