Futures Position Size Calculator
Calculate whole-contract arithmetic capacity from an entered percentage or fixed risk budget, stop distance, contract multiplier, minimum price increment and round-turn cost. See exactly why the next contract exceeds the entered budget.
Enter the risk and contract assumptions
Use the dated MES example or replace every specification with the exact current contract data you verified.
Entered futures capacity result
Futures Position Size 2.0.0.
Capacity calculation audit
Follow the budget, tick, stop and whole-contract floor identities.
On smaller screens, scroll each table horizontally; the page itself remains contained.
| Step | Arithmetic | Result |
|---|
Five contract-count capacity rows
All inputs stay fixed while only the whole-contract count changes.
| Contracts | Modeled risk | Budget difference | Risk / balance | Budget test | Row type |
|---|
How the Futures Position Size Calculator works
Tick value = minimum price increment × contract multiplier
Movement risk per contract = stop distance × contract multiplier
Modeled risk per contract = movement risk + entered round-turn cost
Raw contracts = risk budget ÷ modeled risk per contract
Whole-contract capacity = floor(raw contracts)
Flooring avoids rounding a fractional result upward beyond the entered arithmetic budget. It does not certify that the result is prudent, margin-eligible, liquid or executable.
Audited MES worked example
An entered USD 25,000 balance at 1% creates a USD 250 risk budget. The dated MES example uses a USD 5 index-point multiplier and 0.25-point outright tick, so tick value is USD 1.25. A 10-point stop is 40 ticks and USD 50 movement risk per contract. Adding an entered USD 5 round-turn cost gives USD 55 modeled risk per contract.
USD 250 ÷ USD 55 = 4.545454 raw contracts, floored to 4 whole contracts. Modeled risk is USD 220, leaving USD 30 unused. Five rows cover 2, 3, 4, 5 and 6 contracts; the 5-contract row is USD 25 over the entered budget. At an optional 6,500 entry, four contracts have USD 130,000 modeled notional, which is not margin or maximum loss.
Dated MES contract example
The CME values below were checked on 22 August 2026. They remain editable because transaction type and exchange specifications can change.
| Symbol | Contract multiplier | Outright minimum increment | Derived tick value | Use boundary |
|---|---|---|---|---|
| MES | USD 5 × S&P 500 Index | 0.25 index points | USD 1.25 per contract | Verify exact month, transaction type and current rules |
Assumptions and limits
- Only whole contracts are modeled; no fractional exchange contract is suggested.
- Stop distance and minimum increment must share the same quotation unit.
- The model assumes the loss reaches the entered stop distance exactly. Gaps and slippage can make actual loss larger.
- Only the entered round-turn cost is included. Every unentered fee and charge remains excluded.
- Initial margin, maintenance margin, offsets, broker add-ons, buying power and liquidation are outside the model.
- Optional notional is not cash required, margin, modeled stop risk or maximum loss.
- The result is not an order, safe-size label, suitability decision, forecast or financial advice.
A careful futures sizing workflow
- Define the maximum entered arithmetic budget independently of the calculator.
- Identify the exchange, exact symbol, contract month and transaction type.
- Verify the current multiplier, tick and applicable fee schedule.
- Enter a stop distance in the same quotation unit as the tick.
- Review why the capacity row is within budget and the next row is not.
- Separately verify margin, buying power, liquidity, gap risk and broker controls before any decision.
Frequently asked questions
- Divide the entered risk budget by stop distance times units per contract plus entered round-turn cost per contract, then round down to a whole contract.
- Yes. Percentage mode multiplies entered account balance by the entered percentage. Fixed mode uses the positive USD amount entered directly.
- This model uses whole contracts and does not round a fractional capacity upward beyond the entered arithmetic risk budget. The five-row table shows the capacity row and nearby comparisons.
- The entered risk budget is smaller than the modeled risk for one contract. The calculator does not suggest a tighter stop, larger budget or alternate product.
- Yes. The model adds one nonnegative entered round-turn cost per contract to stop-movement risk before calculating capacity. Every unentered cost and slippage remain excluded.
- No. Optional notional equals entry price times units times whole contracts. Modeled risk uses stop distance and entered costs.
- No. Initial margin, maintenance margin, offsets, broker add-ons, buying power and liquidation thresholds require separate current verification.
- No. It is arithmetic capacity under entered assumptions, not a safe-size label, order instruction, suitability decision, stop-fill guarantee or forecast.
Sources and methodology
- CME Group — Trading Strategies in Your Trade Plan — discusses defining portfolio risk and using it to determine position size.
- CME Group — Calculating Futures Contract Profit or Loss — explains the tick-value and whole-position movement identities.
- CME Group — Micro E-mini S&P 500 contract specifications — identifies the USD 5 multiplier and 0.25-point minimum tick.
- CFTC — Basics of Futures Trading — describes futures obligations and the possibility of losses beyond the initial investment.
The operational contract is Futures Position Size version 2.0.0. Independent fixtures cover percentage and fixed budgets, one-contract and zero-contract boundaries, tick and direct stop-risk reconciliation, exact floor behavior, five capacity rows, optional notional, CSV structure and row-specific invalid inputs.
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Compare broker products separately
The brokers below primarily offer leveraged forex or CFD products, not the MES futures example on this page. Verify the broker’s own symbol, contract size, lot step, margin, spread, commission and financing terms.
Risk warning and affiliate disclosure: Futures and leveraged derivatives are high risk, and losses can exceed the modeled stop or initial funds. Links above are affiliate links; we may earn a commission at no extra cost to you. This calculator is educational and does not provide personalized advice.