Two traders win the exact same 40% of their trades. One finishes the year up; the other blows the account. What separates them is R, the unit that scores every trade as a multiple of what you put at risk. Score your trades in R instead of dollars and the math that actually decides whether you survive a funded account stops hiding behind a flattering win rate.
What R actually is
R is the amount you decide to risk on one trade, measured from your entry to your stop, in dollars or ticks. That is the whole definition. Buy a contract with your stop sitting $300 away and 1R equals $300 for that trade. You set R before you enter, never after.
Every outcome then becomes a multiple of that unit. Hit your stop and you take a -1R loss. Make twice what you risked and that is a +2R win. Scratch at break-even and you booked 0R. It reads like bookkeeping, but it does something powerful. It puts every trade on the same scale no matter the dollar size.
Picture a $300-risk trade next to a $900-risk trade. In dollars they look unrelated. In R they line up perfectly, because a +2R result is the same quality of outcome on each one, even though one made $600 and the other made $1,800. R turns dollars into a unit, and that unit is what lets you measure an edge across hundreds of trades of wildly different sizes.
1R is the distance from your entry to your stop in dollars, fixed the moment you take the trade. Everything after is measured against it.
Expectancy: your per-trade edge
Win rate feels like the headline number. It is not. The number that tells you whether you make money is expectancy: the average R you earn per trade across a large sample.
The formula is short. Expectancy equals (win rate times average win in R) minus (loss rate times average loss in R). Run it honestly over your real results and it returns one figure, the average R you bank per trade. Positive means you have an edge. Negative means you lose over time, no matter how good any single trade felt while it was live.
Work a clean case. Say 40% of your trades win, winners average +2R, losers average -1R. The win side contributes 0.40 times 2, or +0.80R. The loss side contributes 0.60 times 1, or 0.60R against you. Subtract: 0.80 minus 0.60 leaves +0.20R per trade. That trader banks one-fifth of a unit of risk on average, every trade, over a big enough sample.
Now flip the payoff. Same trader, same 40% win rate, but winners make only +1R. The win side is 0.40 times 1, or 0.40R. The loss side is unchanged at 0.60R. Subtract and you get -0.20R per trade. Identical hit rate, identical discipline, opposite result, decided entirely by how much each win pays relative to each loss.
Win rate is the vanity metric. Expectancy is the only honest one, because it is the single number that says whether the system makes money.
Win rate vs payoff
Here is the proof that win rate alone tells you nothing. Put two systems side by side.
System A wins 40% of the time. Winners pay +2R, losers cost -1R. Expectancy: 0.40 times 2 is 0.80; 0.60 times 1 is 0.60; 0.80 minus 0.60 equals +0.20R per trade. Positive. This trader is right less than half the time and still compounds.
System B wins 60% of the time. Winners pay +0.5R, losers cost -1R. Expectancy: 0.60 times 0.5 is 0.30; 0.40 times 1 is 0.40; 0.30 minus 0.40 equals -0.10R per trade. Negative. This trader is right more often and still bleeds out.
The lower win rate makes money. The higher win rate loses money. A high hit rate built on tiny wins and the occasional full -1R loss is a negative-expectancy system in a flattering costume, and being right feels so much like winning that it is the exact trap most struggling traders fall into.
This decides which lever you pull. Most traders try to rescue a losing system by raising their win rate, the hardest variable to move, because it depends on market behavior you do not control. The lever you can actually grab is payoff: the R-multiple you target, set by where you place your profit objective relative to your stop. Cut winners less and let them run toward 2:1 or 3:1 and the math tilts your way without you having to be right more often. Whether bigger targets genuinely net more depends on your win rate not collapsing as you demand farther targets, so test it on your own data rather than assuming.
The break-even win-rate table
Every reward-to-risk ratio has a win rate below which you lose and above which you profit. The formula is exact. Break-even win rate equals 1 divided by (1 plus R), where R is your reward-to-risk ratio, winners averaging +R and losers averaging -1R.
| Reward:Risk | Break-even win rate | You must |
|---|---|---|
| 0.5:1 | 66.7% | beat 66.7% |
| 1:1 | 50.0% | beat 50% |
| 1.5:1 | 40.0% | beat 40% |
| 2:1 | 33.3% | beat 33.3% |
| 3:1 | 25.0% | beat 25% |
| 4:1 | 20.0% | beat 20% |
Read it carefully. The word is "beat," not "hit." At exactly the break-even win rate your expectancy is zero. You need strictly more than the listed figure to make money. A trader running 2:1 who wins exactly 33.3% of the time is treading water; at 34% they are finally ahead.
This is the contrarian's whole case in one table. At 1:1 you have to be right more than half the time, which is genuinely hard. At 3:1 you only need to be right one trade in four. Raise your R-multiple and you lower the win rate you need to survive, and target placement is something you choose, unlike whether the market decides to cooperate.
It assumes wins average exactly +R and losses exactly -1R. Real fills slip and gaps happen, so a loss can run past -1R, which pushes the true break-even slightly above the theoretical number.
R on a funded account
Off a funded account, expectancy is the whole game. On a funded account there is a second, harsher layer that most education skips. You can run a genuinely positive-expectancy system and still fail the challenge or lose the account, because a hard daily loss limit or a trailing drawdown can end you in the middle of a perfectly normal losing streak.
The daily loss limit and the max drawdown define how many R you can lose in a row before you breach. Take an illustrative case for the arithmetic only. If your daily loss limit is $3,000 and 1R is $300, then ten straight -1R losses total $3,000 and end your day, or your account. Those numbers are not a real firm spec, so substitute your own firm's actual limits. A +0.20R-per-trade system still throws losing streaks, so R has to be small enough that a normal streak does not blow through the limit before your edge has room to work.
That reframes the goal. Off-account, you optimize edge over infinity. On a funded account, you survive one specific finite buffer. Positive expectancy is necessary but not sufficient, because the prop layer can kill a winning system mid-streak. Size for survival first, edge second.
The practical move is to size R off your drawdown buffer, the distance to breach, rather than off the headline account balance. The buffer is what actually fails you, not the nominal account size. Many firms also enforce a consistency rule that caps how much of your total profit can come from a single day, which in effect caps how much R you can responsibly book per day. Whether a consistency rule applies at all, whether the drawdown is intraday, end-of-day, static, or trailing, and what the exact numbers are all vary by firm and account type and change over time, so verify the current rule with your firm before you trust any figure. For a deeper breakdown of how those caps interact with daily R, read our piece on prop firm consistency rules, and pair it with the buffer-aware approach in our position sizing guide for funded accounts.
Daily loss limits, drawdown type, and consistency caps differ by firm and change over time. Read your own rulebook. Do not treat any single firm's numbers as universal.
Sizing every trade by R
Fixed-R sizing is the operational discipline that makes everything above measurable. Risk the same R on every trade. Not the same contract count, the same dollar risk. A setup with a tight stop means you trade more contracts; a wide stop means you trade fewer, so the dollar distance from entry to stop stays pinned at your fixed R.
Walk a full example with the arithmetic spelled out. Fix 1R at $300. Your edge is a 40% win rate, winners +2R, losers -1R. Run 100 trades.
- Per-trade expectancy: win side 0.40 times +2R is +0.80R; loss side 0.60 times -1R is -0.60R; total +0.20R per trade.
- Winners in dollars: 40 trades times +2R times $300 equals +$24,000.
- Losers in dollars: 60 trades times -1R times $300 equals -$18,000.
- Net: $24,000 minus $18,000 equals +$6,000.
- In R: $6,000 divided by $300 equals +20R total, which is +0.20R per trade. The dollar result and the expectancy match exactly.
Now hold the win rate and weaken the payoff to 1:1. Expectancy becomes 0.40 times 1 minus 0.60 times 1, which is -0.20R per trade. Over the same 100 trades at $300, that is -$6,000. Same 40% win rate, payoff flipped, account drains. Payoff, not win rate, is the lever, and fixed-R is what keeps the comparison honest, because one bad trade cannot do outsized damage when every trade risks the same unit.
Tie it back to the buffer. At 1R of $300 against an illustrative $3,000 daily loss limit, ten straight losses end the day. A positive-expectancy system still has streaks, so your fixed R has to be small enough that a realistic streak does not breach before your edge plays out. The drawdown math behind recovering from those streaks is its own subject, covered in our drawdown recovery guide.
Common R mistakes
The math is clean. The ways traders break it are predictable.
- Moving the stop wider mid-trade. The instant you slide a stop away from price to dodge the loss, you turn a -1R loss into -1.5R or -2R after the fact. Every expectancy figure you ever ran quietly becomes wrong, because your average loss is no longer -1R.
- Chasing win rate instead of payoff. Traders grind to be right more often, the hardest lever to move, when raising the R-multiple does the same job and sits under their control through target placement.
- Sizing off the balance, not the buffer. The headline account number does not fail you. The distance to breach does. Size R off the buffer.
- Logging only dollars. If you do not record results in R, you cannot compute expectancy over your sample, and you are flying blind on whether the system, not your discipline, is the problem.
- Applying R math where there is no stop. Styles with no fixed stop, such as some mean-reversion or "manage it live" approaches, have no clean 1R, so expectancy is unmeasurable and the framework misleads more than it helps. R math assumes a defined, respected stop.
Use this before and after every trade. Before entry: R is defined in dollars entry-to-stop and equals your usual fixed R; contract size is set so the dollar risk matches that R; your reward target clears the break-even table for your real win rate; R is small enough that a realistic streak will not breach your limits; today's planned trades stay inside any consistency cap. After the trade: confirm the stop did not move against you, and log the result in R. Periodically: recompute expectancy over your last N trades and, if it is not clearly positive, fix the system rather than blaming your nerves.
A trade copier multiplies whatever expectancy you already have across every account at once. Copy a negative-R system and you lose faster on more accounts. Fix the per-trade R math first.
One last honest tradeoff. Expectancy is a long-run average, and over a small sample variance dominates, so a positive-expectancy trader can still hit a drawdown that breaches a funded account in any given week. Fixed-R also does not capture clustered losses, slippage, gaps, or fills worse than your stop in fast futures markets, where a real -1R can run past -1R. The math is necessary, not a guarantee, so build margin for the real world. And before you ever consider scaling a system across accounts with a tool like Thor, make sure the per-trade R is right, because a copier only amplifies the edge or the leak you already have. The discipline of holding to fixed R under live pressure is its own subject, examined in our guide to trading psychology for funded accounts.
Frequently asked questions
What is an R-multiple in trading?
An R-multiple expresses a trade's outcome as a multiple of the amount you risked. 1R is the dollar distance from your entry to your stop, decided before you enter. A trade that hits your stop is normally a -1R loss, and a trade that makes twice your risk is a +2R win. R lets you compare trades of different dollar sizes on a single scale.
How do you calculate expectancy?
Expectancy equals (win rate times average win in R) minus (loss rate times average loss in R). The result is the average R you earn per trade over a large sample. A positive number means you have an edge, while a negative number means you lose over time no matter how good individual trades feel. For example, a 40% win rate with +2R winners and -1R losers gives 0.80 minus 0.60, or +0.20R per trade.
Can a system with a low win rate still be profitable?
Yes. A system that wins only 40% of the time with +2R winners and -1R losers earns +0.20R per trade, which is profitable. A system that wins 60% of the time with +0.5R winners and -1R losers earns -0.10R per trade, which loses money. Win rate alone tells you nothing about profitability; payoff relative to risk is what decides it.
What win rate do you need to break even at different reward-to-risk ratios?
Break-even win rate equals 1 divided by (1 plus R), where R is your reward-to-risk ratio. At 1:1 you must beat 50%, at 2:1 you must beat 33.3%, and at 3:1 you must beat 25%. These figures assume winners average +R and losers average -1R, and you need strictly more than the listed rate to profit, because at exactly the break-even rate your expectancy is zero.
How should you size R on a funded prop account?
Size R off your drawdown buffer, the distance to breach, rather than off the headline account balance, because the buffer is what actually fails you. Keep R small enough that a realistic losing streak will not blow through your daily loss limit or trailing drawdown before your edge plays out. Daily limits, drawdown type, and consistency caps vary by firm and change over time, so verify the current rule with your firm.
Why is moving a stop the most dangerous R mistake?
When you slide a stop wider mid-trade to avoid taking a loss, you turn a -1R loss into a -1.5R or -2R loss after the fact. That breaks every expectancy calculation you have ever run, because your average loss is no longer -1R. The R framework only works with a defined, respected stop, so a single stop-move can quietly flip a positive-expectancy system into a negative one.
Does a trade copier improve your expectancy?
No. A copier propagates one decision across many accounts at once, which only scales whatever expectancy you already have, positive or negative. Copy a negative-expectancy system and you lose faster on more accounts simultaneously, and an oversized-R trade or a stop-move mistake gets multiplied across every account. Fix the per-trade R math first, then consider scaling it.
Should you always aim for a higher reward-to-risk ratio like 3:1?
Not automatically. A higher R-multiple lowers the win rate you need to break even, since 3:1 only needs to beat 25%, but farther targets tend to be hit less often. Whether raising your R-multiple actually nets more money depends on your win rate not collapsing as you demand bigger targets, so test the tradeoff on your own results rather than assuming a fixed ratio is best.