A reward-to-risk ratio compares the gain if a target is hit with the loss if the stop is hit. Profitability also depends on the observed win rate, costs, slippage and whether trades follow the same…
Understand the mechanism
A reward-to-risk ratio compares the gain if a target is hit with the loss if the stop is hit. Profitability also depends on the observed win rate, costs, slippage and whether trades follow the same tested rules. Expectancy per trade can be written P(win) × average win minus P(loss) × average loss minus average costs. A positive historical estimate can still fail in the future.
Before applying this topic in a live market, write down the information available before the decision. Distinguish a fact confirmed by a platform specification or official source from an interpretation drawn from a chart. If a key data point is missing, treat it as unknown rather than filling it with a convenient estimate.
Worked example or scenario
With a 40% win rate, average winners of 2R and losers of 1R, gross expectancy is 0.4×2 − 0.6×1 = +0.2R. If average execution cost is 0.25R, net expectancy becomes −0.05R.The numbers and scenarios in this example are educational illustrations. They are not live quotes, account-specific contract terms, backtested guarantees or a suggestion to place this trade. Consider how the outcome changes when costs, a different contract multiplier, or a faster market are introduced.
Common mistakes and limitations
Calling every 1:3 target a profitable system without measuring win rate, fill probability and actual net costs.
Check whether any assumption depends on a fixed spread, a guaranteed fill, a historical relationship remaining stable, or the availability of a financial product in your country. In practice, execution rules and platform legal entities differ. A correct formula using an incorrect contract multiplier can still produce a dangerously wrong position size.
Four-point practical checklist
- 1
Step 1
Identify the exact instrument and contract terms before doing any arithmetic.
- 2
Step 2
State the risk and assumptions in account currency, not only in chart points.
- 3
Step 3
Check current primary-source information and write down what could invalidate the idea.
- 4
Step 4
Calculate break-even probability for average wins of 1R, 1.5R and 2R before costs.
Practice assignment
Calculate break-even probability for average wins of 1R, 1.5R and 2R before costs.
Complete the task in a journal, spreadsheet or demo account and keep a record of your assumptions. If you are unable to explain the possible loss in your own account currency, do not substitute a larger position for a missing calculation.
Reflect and self-check
Does understanding this lesson guarantee profit?
No. Understanding mechanisms helps evaluate decisions; it cannot predict market movements or remove trading losses.
Can I use this lesson with any broker?
The principles may transfer, but prices, product rules, contract multipliers, protections and country eligibility must be checked for each provider.