The formula
Contracts = Risk per trade ($) ÷ (Stop distance in ticks × Tick value)
Always round down. If the answer is below one, the trade doesn’t fit your risk on that contract.
Worked examples
ES with a $500 risk limit
Stop 6 points away = 24 ticks × $12.50 = $300 per contract. $500 ÷ $300 = 1.67 → 1 contract (actual risk $300).
NQ with the same limit
Stop 20 points away = 80 ticks × $5 = $400 per contract → 1 contract. Widen the stop to 30 points ($600) and the answer is zero — the trade doesn’t fit.
Switching to micros
That 30-point NQ stop costs $60 per MNQ contract. $500 ÷ $60 = 8 MNQ, risking $480. Micros let you keep the stop where the chart says it belongs instead of shrinking it to fit a full-size contract.
Run your own numbers in the position size calculator and check contract values in the tick value calculator.
Choosing your risk per trade
Many traders risk 0.25%–1% of their account per trade. In a prop-firm evaluation, size against the drawdown, not the account size: on a $50,000 account with a $2,000 drawdown, $500 per trade means four straight losses end the attempt. The prop firm challenge calculator shows how sizing changes your odds.
Common sizing mistakes
- Sizing up after a loss to “make it back” — the classic road to a blown account.
- Tightening the stop to fit a bigger size — the stop goes where the trade is wrong, not where your size wants it.
- Ignoring commissions on high-contract-count micro trades.
FAQ
How many futures contracts should a beginner trade?
Usually micros, sized so a full stop costs well under 1% of the account.
Is it better to trade 1 ES or 10 MES?
The dollar exposure is the same, but 10 MES lets you scale in and out and size more precisely; commissions are higher.