Position size answers one question: how many contracts can I trade so that hitting my stop loses only the amount I decided to risk?
The formula
Contracts = (account balance × risk %) ÷ (stop distance in points × dollar value per point), rounded down.
Worked example
A $50,000 account risking 1% per trade can lose $500. With a 10-point stop:
| Symbol | Contract | $ per point | Risk per contract (10 pts) | Max contracts |
|---|---|---|---|---|
| ES | E-mini S&P 500 | $50.00 | $500.00 | 1 |
| MES | Micro E-mini S&P 500 | $5.00 | $50.00 | 10 |
| NQ | E-mini Nasdaq-100 | $20.00 | $200.00 | 2 |
| MNQ | Micro E-mini Nasdaq-100 | $2.00 | $20.00 | 25 |
| YM | E-mini Dow | $5.00 | $50.00 | 10 |
| MYM | Micro E-mini Dow | $0.50 | $5.00 | 100 |
| CL | Crude Oil | $1,000.00 | $10,000.00 | 0 |
| MCL | Micro Crude Oil | $100.00 | $1,000.00 | 0 |
| GC | Gold | $100.00 | $1,000.00 | 0 |
| MGC | Micro Gold | $10.00 | $100.00 | 5 |
When the result is 0, even one contract risks more than your limit: tighten the stop only if the setup allows it, or use the micro contract.
Do it without the math
The Funded Trader Toolkit spreadsheet has this calculator built in: enter balance, risk %, entry and stop, and it returns contracts for ES, MES, NQ, MNQ, YM, MYM, RTY, M2K, CL, MCL, GC and MGC, plus forex lots and stock shares. See also prop-firm challenge FAQ.
Free download: the Pre-Trade Checklist + Daily Risk Card (printable PDF). Want every tool at once? The Prop Firm Trader Bundle has all four spreadsheets for $29.99. Or try the free position size calculator.
For education and record-keeping only. Not financial advice. Trading involves substantial risk of loss. Prop firms set and change their own rules; check your firm's current rules.