A futures stop distance is only the starting point for trade risk. Prop traders should add estimated commissions and slippage because the account is measured on actual fills and net results. A trade planned to lose $200 can breach a tight threshold if execution costs are ignored.
Complete risk formula
Estimated trade risk = stop-distance risk + round-turn commissions and fees + slippage allowance
Stop-distance risk = ticks to stop × tick value × contracts
Slippage allowance = assumed slippage ticks × tick value × contracts
Worked micro-contract example
Assume:
- 20 ticks to the stop
- $0.50 per tick
- 10 micro contracts
- $12 estimated round-turn costs
- Two ticks of possible slippage
| Component | Calculation | Amount |
|---|---|---|
| Stop risk | 20 × $0.50 × 10 | $100 |
| Slippage allowance | 2 × $0.50 × 10 | $10 |
| Costs | Estimate | $12 |
| Total estimated risk | Sum | $122 |
The charted stop suggests $100, but the practical estimate is $122.
Why stop orders can slip
A stop-market order becomes a market order after its trigger is reached. The trigger price is not a guaranteed execution price. During fast movement, thin liquidity or a gap, the order can fill at a worse average.
A stop-limit order controls the accepted price but creates another risk: it may activate and remain unfilled while the market continues against the position.
Neither choice removes execution risk.
Commissions affect both losses and targets
Round-turn cost includes the fees incurred to enter and exit. Frequent scalping can produce meaningful costs even when individual trades are small.
If a prop evaluation target is $3,000 and expected costs are $15 per completed trade, 40 round turns create $600 of cost. Gross trading profit would need to exceed the target by enough to cover those charges in the account’s net result.
Do not invent a universal commission number. Use the rate shown for the selected platform, connection and contract.
Compare risk with every active limit
Before transmitting, compare estimated trade risk against:
| Limit | Question |
|---|---|
| Maximum drawdown cushion | How much room remains before the hard floor? |
| Daily loss allowance | How much can still be lost today? |
| Personal session stop | Does this trade fit the plan? |
| Contract cap | Is the quantity permitted? |
| Margin and buying power | Will the platform accept the order? |
Use the smallest remaining allowance as the binding constraint.
Slippage stress test
Calculate three scenarios:
| Scenario | Slippage assumption |
|---|---|
| Normal | 0–1 tick |
| Fast market | 2–4 ticks |
| Severe event | Strategy-specific larger allowance |
This is not a prediction. It shows whether the account survives a worse fill without touching a rule threshold.
Practical position-sizing steps
- Select the correct futures contract and month.
- Convert the stop distance into ticks.
- Multiply by tick value and contracts.
- Add round-turn commissions and fees.
- Add a reasonable slippage allowance.
- Compare the total with current prop limits.
- Reduce quantity when the stressed result is too close to a threshold.
- Verify the actual fill and update remaining risk.
Common errors
Using point value instead of tick value
Confirm both minimum tick and dollar value for the exact contract.
Ignoring partial fills
Several fill prices can change the average entry and exit.
Counting only one side of commission
Use the estimated round-turn cost for a planned entry and exit.
Trading directly against the threshold
Leave room for costs, slippage and platform calculations rather than setting planned loss exactly at the breach level.
CME Group’s education resources explain common futures order types. Contract specifications and actual platform fees should be checked before trading.
Bottom line
Size futures trades from net risk, not stop distance alone. Add commissions and a slippage allowance, stress-test the result and compare it with the account’s remaining drawdown and daily limit.