Position Sizing for Options Traders:
The Only Rule That Saves Your Account
Most accounts don't blow up because the trader was wrong. They blow up because the trader was right 60% of the time but sized the losing 40% large enough to erase everything.
Why options sizing is different
A 100-share position in AAPL at $175 costs $17,500. A 10-contract AAPL call at $1.50 costs $1,500 and controls 1,000 shares. The options position has 10x the leverage. A 50% move in AAPL stock is a once-in-a-decade event. A 50% move in a 0DTE option can happen in 15 minutes.
This leverage is why options traders can turn $500 accounts into $5,000. It's also why they turn $10,000 accounts into $1,200. The math works both ways with equal speed.
The 1% rule and why it matters
Risk no more than 1–2% of your total account on any single trade. On a $10,000 account, that's $100–$200 maximum loss per trade. This isn't about being timid — it's about staying in the game long enough to find your edge.
With 2% risk per trade, you need to lose 50 consecutive trades to go from $10,000 to approximately $3,600. That's survivable. With 10% risk per trade, 10 consecutive losses takes you from $10,000 to $3,487 — and 10 consecutive losses is not unusual when you're learning.
How to calculate max contracts
Step 1: Define your max dollar loss per trade (1–2% of account).
Step 2: Define your stop — the price at which you'll exit the option if wrong.
Step 3: Max contracts = max loss ÷ (entry price − stop price) ÷ 100.
Account: $10,000. Max risk: 2% = $200.
SPY 475 PUT at $2.10. Stop at $1.50 (−$0.60 per share).
Max contracts = $200 ÷ ($0.60 × 100) = $200 ÷ $60 = 3.3 → 3 contracts max.
Buying 10 contracts on this trade is a $600 stop-out — 6% of account on one trade.
The sizing escalation trap
After a loss, your brain wants to recover quickly. The natural impulse is to increase size on the next trade — if you just lost $300 at 3 contracts, maybe 6 contracts will win it back faster. This is position-size escalation after a loss, and it's the fastest way to turn a bad day into a catastrophic day.
Tempera flags this pattern as "revenge trading via size escalation" — and it is. The counter-rule: after a losing trade, size DOWN on the next one. Take your next 2–3 trades at half your normal size. Let yourself rebuild confidence with smaller risk before returning to full size.
Daily loss limits
Your position sizing rule only protects you per trade. You also need a daily loss limit — a dollar amount at which you stop trading for the day regardless of how many trades you've taken.
A common starting point: 3–5% of account as daily max loss. On a $10,000 account that's $300–$500. When you hit it, you close your platform and walk away. No exceptions. This is what separates a bad day ($300 loss) from a blown account ($3,000 loss over 6 hours of revenge trading).