Position sizing for options traders: protect the account first
A practical guide to sizing options trades — risk-per-trade, defined vs. undefined risk, and the sizing mistakes that blow up accounts — plus how to enforce it with goals and alerts.
Most options traders obsess over entries and ignore the one decision that determines whether they survive: how much to risk. You can have a great edge and still blow up if your sizing is reckless — and you can have a mediocre edge and grind out a living if your sizing is disciplined. Size is the lever that matters most.
Start from risk, not from conviction
The professional approach is to decide what you’re willing to lose on a trade first, then size the position to that number — not to size up because you “feel good” about it. A common rule is risking a fixed small percentage of your account per trade (many traders use 1–2%). Conviction belongs in your trade selection, not in your size.
Defined vs. undefined risk
Options make sizing trickier than shares because risk isn’t always obvious. For a long call or a defined-risk spread, your max loss is known up front, so sizing is clean: max loss × contracts ≤ your risk budget. For undefined-risk trades (naked short options), the “max loss” is theoretically huge — size those far smaller, and know your real exposure before you put it on.
- Fix your risk per trade — a set dollar or percentage amount, decided in advance.
- Size to max loss — contracts × max loss should stay within that budget.
- Shrink undefined-risk trades — naked positions need far less size than spreads.
- Never average down to “make it back” — that’s sizing driven by emotion, not plan.
Amateurs ask how much they can make on a trade. Professionals ask how much they can lose — and size to that answer.
Make the rule enforce itself
A sizing rule you have to remember in the heat of a trade is a rule you’ll break. The fix is to externalize it: set a max position size and a max daily loss as hard numbers, and let alerts fire the moment you cross them. In MyTradeLens you can set those goals and get breach alerts, then review the trades that broke a rule each week — which is how the discipline actually sticks.