One standard options contract represents 100 shares of the underlying stock. This is called the "contract multiplier." When you see an option quoted at $3.50, you multiply by 100 to get the actual cost: $350. When a $50 stock moves $1, each option contract's intrinsic value changes by $100 (not $1). This 100-share multiplier is the single most common source of confusion for new options traders.

Why 100 Shares?

Stocks traditionally traded in "round lots" of 100 shares. Options were designed to correspond to one round lot, making hedging straightforward. One put contract hedges exactly 100 shares of stock. The standard has stuck since options began trading on the CBOE in 1973.

How Contract Size Affects Your Math

Cost calculation:

  • Option price: $4.25 per share
  • Actual cost per contract: $4.25 × 100 = $425
  • Buying 3 contracts: $425 × 3 = $1,275

    • Profit calculation:

  • You buy a $150 call for $5.00 ($500). Stock goes to $165.
  • Intrinsic value at expiration: $165 − $150 = $15 per share
  • Total value: $15 × 100 = $1,500
  • Profit: $1,500 − $500 = $1,000

    • Assignment obligation:

  • You sell a cash-secured $100 put. If assigned, you must buy 100 shares at $100 = $10,000 cash needed.
  • You sell a covered call. If assigned, you must deliver 100 shares.

    • Position Sizing Implications

    The 100-share multiplier means even a "small" options trade can control meaningful capital.

    | Stock Price | Shares Controlled (1 contract) | Capital Controlled | $15 (SoFi)100$1,500 $50 (Intel)100$5,000 $190 (Apple)100$19,000 | $420 (Microsoft) | 100 | $42,000 |

    Selling a cash-secured put on a $200 stock requires $20,000 in your account. This is why many traders with smaller accounts focus on lower-priced stocks or use spread strategies that reduce capital requirements.

    Exceptions to the 100-Share Standard

    Stock splits and special dividends can create non-standard contracts. If a stock does a 3-for-2 split, existing options contracts might be adjusted to 150 shares at an adjusted strike. These "adjusted" options can be confusing and often have poor liquidity.

    Mini options were introduced in 2013 for a few popular stocks, covering only 10 shares per contract. They were discontinued in 2014 due to low demand, though there's periodic talk of bringing them back.

    Index options use a cash multiplier. One SPX option has a notional value of the index level × 100. With SPX at 5,200, one contract controls $520,000 in notional value.

    Practical Tips

  • Always multiply by 100 when evaluating cost or profit. A $2.00 option isn't $2 — it's $200.
  • Check your order before submitting. Buying 10 contracts of a $5 option costs $5,000, not $50.
  • Match contracts to shares. If you own 200 shares, sell 2 covered calls (not 1 or 3).
  • Use OptionsPilot's calculators to see real dollar amounts for premiums, max profit, and max loss so the 100x multiplier is handled automatically.

    • The 100-share standard also means fractional share traders can't directly sell covered calls. You need whole lots of 100. If you own 150 shares, you can sell 1 covered call (covering 100 shares), with 50 shares uncovered.