Method 03 · Risk engine

Risk/reward and position sizing without guesswork

Calculate trading risk/reward, risk per unit and position size. Learn how 1R, account risk, entry, stop, target, fees and slippage fit together.

Direct answer

Risk/reward compares the distance from entry to target with the distance from entry to stop. Position size then converts your chosen account risk into units. A 2:1 ratio is not automatically good; probability, costs, execution and invalidation still matter.

What to remember

  • Define account risk before calculating size.
  • 1R is your planned loss at the stop.
  • A tighter stop increases size and execution sensitivity.
  • Fees, spread and slippage reduce the displayed ratio.
1R

Risk/reward and position-size calculator

Use your own numbers. The calculator runs in the browser and does not place an order.

Direction
Reward / risk2 : 1
Risk per unit2
Reward per unit4
Risk amount50
Position size (units)25

Educational estimate before fees, spread, slippage, funding and currency conversion.

The formula and the meaning of 1R

For a long trade, unit risk equals entry minus stop and unit reward equals target minus entry. For a short trade, risk equals stop minus entry and reward equals entry minus target. Reward divided by risk gives the headline ratio.

If you risk 1% of a $5,000 account, 1R equals $50. A full stop is approximately −1R and a target twice as far as the stop is approximately +2R before costs. Expressing outcomes in R makes instruments and account sizes comparable.

HyperFX recalculates R:R from numeric levels in code; it does not trust a ratio written by the AI model.

Position size connects the chart to the account

Position size in units equals risk amount divided by risk per unit. With $50 risk and a $2 stop distance, the theoretical size is 25 units. Leverage does not reduce the economic loss at the stop; it only changes required margin and liquidation risk.

A very tight stop creates a large theoretical size and makes spread, wick noise and slippage proportionally more important. Cap size, check contract multipliers and convert quote currencies where necessary.

  • Account size × risk % = risk amount
  • Risk amount ÷ stop distance = theoretical units
  • Check tick value, lot size and contract multiplier
  • Reduce for correlated open positions

Ratio is useful only with probability and costs

A strategy that wins 40% at +2R and loses 60% at −1R has a theoretical expectancy of +0.2R before costs. Changing the average win, average loss or execution rate changes the result. That is why a single setup's R:R cannot prove a strategy.

Use the calculator as a pre-trade consistency check, then validate real expectancy from a sufficiently large demo or live journal. Avoid increasing risk after a losing streak or because a setup has high confidence.

  • Expected R = win rate × average win R − loss rate × average loss R
  • Model partial exits and breakeven consistently
  • Include fees, spread, funding and slippage
  • Set a portfolio-level risk cap

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Educational information only. Not financial advice. AI and market data can be wrong; trading can result in loss.

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Risk Reward Ratio and Position Sizing Calculator | HyperFX