Options Position Size Calculator
This calculator tells you how many contracts you can trade without risking more than a chosen percentage of your account. It's the simplest guard against oversized positions.
Your risk budget is $500, which fits 1 contract with $340 at risk (1.36% of the account).
Educational estimate, not advice.
How it works
Your risk budget is account size × risk %. Divide by the max loss per contract and round down.
- Risk budget = A × R ÷ 100
- Max loss per spread = (W − C) × 100
- Contracts = floor(budget ÷ L)
- Capital at risk = contracts × L
Worked example
A $25,000 account risking 2% has a $500 budget. A spread with $340 max loss allows 1 contract, risking 1.36% of the account.
Limitations
Uses max loss at expiration; real losses can differ with gaps, early exits and fees.
Questions
How many contracts should I trade?
Enough that max loss stays within your per-trade risk limit — many traders use 1–2%.
What if the result is 0?
The trade is too large for your budget. Use a narrower spread or skip it.
Why warn above 5%?
Risking more than 5% per trade can cause large drawdowns after a few losses.
Related
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