Risk reward ratio and breakeven win rate, after costs
A planned risk/reward ratio sets a breakeven win rate of 1 ÷ (1 + ratio). Costs and slippage lower the ratio you actually realize, so planned 2:1 is not realized 2:1.
Start in plain English
The risk reward ratio compares how much a trade aims to make with how much it plans to risk. A trade with a 10-cent target and a 5-cent stop has a planned ratio of 2:1, often written "2R". This lesson covers what that ratio does and does not tell you, and why, for a small-cap scalper, the ratio on paper and the ratio in the account are often far apart.
The core idea: a planned risk/reward ratio sets a breakeven win rate, and costs raise it.
Breakeven win rate = 1 ÷ (1 + ratio), where ratio = average win ÷ average loss.
At 2:1, a trader breaks even by winning 1 ÷ 3 = 33.3% of trades, before costs. That is the planned version. The realized version uses the average win and average loss after commissions, fees and slippage. For a scalp with a small stop, those few cents are a large share of each outcome, so the realized ratio is lower and the breakeven win rate higher. Planned R:R is not realized R:R.
A ratio says nothing about how often the target is reached. That frequency is the other half of Expectancy.
A worked example: breakeven for a 10-cent scalp
All numbers here are Illustrative. Pellworth Systems is fictional.
The plan. Buy 1,000 shares of Pellworth Systems at $5.20. Stop $5.15 (5 cents). Target $5.30 (10 cents). Planned ratio: 10 ÷ 5 = 2:1. Planned breakeven win rate: 1 ÷ (1 + 2) = 33.3% (computed, Illustrative).
Add costs. Commissions and fees are $0.005 per share round trip.
- Win after costs: $0.10 − $0.005 = $0.095 per share.
- Loss after costs: $0.05 + $0.005 = $0.055 per share.
- Ratio: 0.095 ÷ 0.055 = 1.73:1. Breakeven: 0.055 ÷ (0.095 + 0.055) = 36.7%.
Add one cent of stop slippage. Stops often fill past their price in a fast small cap.
- Loss: $0.05 + $0.01 + $0.005 = $0.065 per share.
- Ratio: 0.095 ÷ 0.065 = 1.46:1. Breakeven: 0.065 ÷ (0.095 + 0.065) = 40.6% (computed, Illustrative).
Half a cent of fees and one cent of slippage moved the breakeven win rate from 33.3% to 40.6% (computed, Illustrative). On a day-trade plan with a 50-cent stop, the same cents would move it by less than one percentage point. That is the scalper's version of this formula: the smaller the stop, the more the cents matter.
If your plan has frequent scratches, they also count. With scratches, breakeven is where win rate × average win equals loss rate × average loss plus scratch rate × average scratch cost; the simple formula assumes every trade is a win or a loss.
Odds box: breakeven win rates
These figures are arithmetic, not findings about any setup. Whether a plan reaches its target often enough to clear its breakeven is a question for a counted sample, after costs.
Planned vs. realized R:R
The planned ratio is set before entry: target distance ÷ stop distance. The realized ratio comes from the log: average net win ÷ average net loss. Four things usually separate them for a scalper:
- Costs. Fixed cents per share, subtracted from every win and added to every loss.
- Entry slippage. A late fill shortens the distance to the target and lengthens the distance to the stop.
- Stop slippage. Stops trigger at their price and fill at the next available one.
- Exit behaviour. Taking profits before the target, or moving a stop, changes both averages.
Track all four. The Trading Journal shows realized results from real broker fills on Plus and above; for practice trades, the course practice log has columns for planned and realized R.
Two paths from the same plan
All numbers here are Illustrative.
The same trader runs the Pellworth-style plan, planned at 2:1, for 20 trades in each of two weeks. In both weeks, 8 of 20 trades are wins (40%). Only the fills and exits differ.
Path AA week where fills cooperate
Liquid conditions, mostly one-cent spreads. All 8 wins reach the target at +1.90R after costs. Of 12 losers, 5 hit the stop at −1.10R; 7 are cut by the time stop at about −0.63R on average.
Path BA week of thin books
Spreads of three to five cents. Entries fill late, so 3 wins reach the target at only +1.50R; 5 more are closed at the time stop with small gains of +0.35R. All 12 losers hit the stop and slip, averaging −1.30R.
Review note: same plan, same 2:1 on paper, same 40% win rate (Illustrative). One week realized 2.3:1, the other 0.6:1. The difference came from fills, spreads and exits, not from the win rate. The rest of this lesson looks at fixed-ratio rules and at what shifts the realized ratio.
Why "minimum 2:1" rules are conditional
Many trading guides state a fixed rule such as "only take trades with at least 2:1". The arithmetic behind it is sound: a higher ratio lowers the breakeven win rate. The rule leaves out three conditions:
- Frequency trades off against ratio. A target twice as far away is usually reached less often. Expectancy combines both. In an Illustrative version of the Pellworth plan with no scratches, a 10-cent target reached on 45% of trades gives 0.45 × 1.90 − 0.55 × 1.30 = +0.14R per trade. Moving the target to 20 cents (planned 4:1, +3.90R after costs) looks better on paper, but if it is reached on only 25% of trades the result is 0.25 × 3.90 − 0.75 × 1.30 = 0.00R. The better ratio produced the worse process. Which share a target is actually reached at is something only a counted sample can tell you.
- Costs shrink small ratios unevenly. A 2:1 scalp with a 5-cent stop can realize less than a 1.5:1 day trade with a 20-cent stop, as the exercises show.
- The stop sets the ratio as much as the target. Tightening a stop to improve the ratio raises the chance of being stopped by ordinary noise. Where a stop goes covers that trade-off.
A ratio rule is a constraint on the plan, not a measure of edge.
Observe vs. infer
At the end of Path B's week (Illustrative):
| What the log shows (observed) | What a trader might infer | Why it is not established |
|---|---|---|
| Win rate 40%, the same as Path A's week | "Same performance as last week" | The realized ratio fell from 2.3:1 to 0.6:1 |
| Average loss −1.30R against a planned −1R | "Unlucky stops" | Spreads were visibly wider; slippage at that spread is expected, not rare |
| 5 wins closed at the time stop with small gains | "Good discipline taking profits" | Small time-stop wins lower the average win; whether that helps is a question for the expectancy |
| A planned 2:1 on every trade | "These were 2:1 trades" | They were 2:1 plans; the trades realized 0.6:1 on average |
What shifts the odds
These shift the realized ratio mechanically; they are not FennEdge findings:
- Spread at entry relative to the stop. A 3-cent spread on a 5-cent stop is 60% of the risk.
- Book depth relative to size. Larger size into a thin book slips more on both entries and stops.
- Order type. Marketable limits cap entry slippage at the cost of missed fills.
- Time stops. They convert some full losses into partial ones and some wins into small ones.
- Halts. A gap through the stop can turn one trade into several R of loss.
Cost of being wrong
For the Pellworth plan at 1,000 shares, 1R = $50 (Illustrative):
| Outcome | Per share | R after costs | Dollars |
|---|---|---|---|
| Target, filled at plan | +$0.095 | +1.90R | +$95.00 |
| Target after a 2¢ late entry | +$0.075 | +1.50R | +$75.00 |
| Stop, no slippage | −$0.055 | −1.10R | −$55.00 |
| Stop, 1¢ slippage | −$0.065 | −1.30R | −$65.00 |
| Stop, 5¢ slippage in a fast drop | −$0.105 | −2.10R | −$105.00 |
Treating the plan's 2:1 as the realized ratio understates the breakeven win rate by about 7 percentage points in the one-cent case, enough to turn a modestly positive process negative.
How many trades before this means anything
A realized ratio is an average of averages, and both the average win and the average loss carry error. With 20 trades of which 8 win, the average win rests on 8 numbers. A few slipped stops or one halt can move the realized ratio sharply. How many trades before your numbers mean anything shows how wide the uncertainty is at 20, 50 and 100 trades.
What this lesson does not claim
- It does not claim any ratio is the right one. Ratios here are Illustrative, and breakeven win rates are arithmetic.
- A ratio is not a probability. A 3:1 plan can have negative expectancy if the target is rarely reached.
- Pellworth Systems, both weeks and all costs are fictional.
Go deeper
- FennEdge first.
- If you trade live, the Trading Journal syncs real fills from supported brokers, so realized wins and losses are net of your actual fees (viewing them needs Plus or above; fee detail on Pro and Max, as of 2026-10-05). It holds broker-synced trades only, not simulated or practice entries.
- The planned DAS Hotkey Script Builder (not live as of 2026-10-05) is designed to generate risk-based entry keys where shares follow from dollar risk and stop distance. Its scripts had not yet been run in a DAS client, so test any generated script in a simulator first.
- The DAS course lesson Sizing lab works through share calculations from a fixed dollar risk.
- Partial exits. Selling part of a position at a first target changes both the average win and the realized ratio; the Advanced course covers scaling.
- Stop distance vs. noise. A tight stop improves the planned ratio and raises the share of trades stopped by ordinary fluctuation. See Where a stop goes.
- Related: ECN fees for the cost line; Slippage for measuring fills; Position sizing.
Exercises
Six exercises follow this lesson: three concept checks (what a planned ratio tells you, why a scalper's realized ratio falls further, why fixed-ratio rules are conditional), two calculations (a cost-adjusted breakeven win rate and a realized ratio from a log) and one scenario comparing a 2:1 scalp with a 1.5:1 day trade after costs. Exercises, answers and progress are available after signing in.
Primary sources
- FINRA. Frequent Intraday Trading: Understanding the Basics.
- FINRA. Order types (a stop order triggers at the stop price and fills at the next available price).
Sources checked 2026-10-05. Pellworth Systems and all prices, ratios, practice weeks and costs in this lesson are fictional and Illustrative; breakeven win rates are computed from the stated ratios. This lesson is education, not a recommendation to buy or sell any security. Past patterns do not indicate future results.