The 100-Share Contract Multiplier

US equity options quotes are almost always per share, but one standard contract controls 100 shares unless the symbol is a mini or adjusted product.

Forgetting the 100× multiplier is the most common beginner math error.

Scale every dollar figure

Per-share quote	Per contract (×100)
Premium $2.00	$200 cash to buy
Intrinsic $1.50 ITM	$150 intrinsic per contract
$0.10 bid-ask spread	$10 friction per contract round trip

Profit: If you buy a call for $2.00 and sell for $3.00, gain is $1.00 × 100 = $100 per contract before fees.

Buying power

Brokers display debit as premium × 100 (plus fees). A $5 option is not $5 total, it is about $500 per contract plus commissions.

Do not multiply by 100 twice when reading statements.

Breakeven at expiry (long call)

Stock must exceed strike + premium per share.

Example: $100 strike, $2.50 premium → breakeven $102.50 at expiry. Max loss $250 per contract if worthless.

Model this in long call builder view.

Spreads

Net debit $1.20 per share on a bull call spread → $120 paid per spread. Max loss on a vertical is often width minus credit, still scaled by 100.

P/L sensitivity to stock move

A $1 move in stock changes intrinsic by about $100 per contract per ITM point for a standard delta-1-like move (simplified; delta varies).

Mini and adjusted contracts

Some symbols trade 10-share minis (multiplier 10). After splits or special dividends, OCC may list non-standard deliverables. Read the option symbol detail if contract size looks odd.

Index options use their own multipliers (SPX famously large).

ThetaViz display

Charts and metrics usually show per-share or total consistent with the UI label. When comparing to broker, confirm which unit you are viewing.

Worked example: two contracts vs one

You buy two calls at $2.00 per share.

• Debit: $2.00 × 100 × 2 = $400 plus fees.
• If each contract rises to $3.00, gain is $1.00 × 100 × 2 = $200 total.

Sizing mistakes often come from multiplying contracts twice or forgetting the 100 on premium.

Worked example: credit spread dollars

Bull put spread: sell $100 put at $2.00, buy $95 put at $0.80. Net credit $1.20 per share.

• Cash collected: $120 per spread (one contract each leg).
• Max loss if stock below $95 at expiry: ($5.00 − $1.20) × 100 = $380 per spread.

Width is $5 between strikes; credit reduces risk.

Assignment and the multiplier

Assigned on one short put at $100 strike: you buy 100 shares per contract. Two short puts → 200 shares. Margin and buying power scale the same way.

Index and futures multipliers (awareness)

SPX options use a large dollar multiplier (historically $100 per index point; verify current specs). Futures options use contract-specific multipliers. Always read the product sheet before mixing equity mental math with index trades.

Mental checklist before you click buy

1. Quote is per share.
2. Multiply premium by 100 for one contract cash.
3. Multiply again by number of contracts.
4. Max loss uses the same scaling.

Corporate actions

Stock splits adjust strikes and multipliers (for example 2-for-1 split may double contracts at half strikes). Special dividends can cause non-standard deliverables. Read OCC notices in your broker app when symbols look odd.

Cash settlement on some products

Index and some exotic options settle cash. P/L still scales by the contract multiplier in the spec. Do not assume every product delivers 100 shares.

Comparing P/L to stock percent

Stock up 2% on $100 is $2 per share. Call up 50% on $2 premium is $1 per share on the option, $100 per contract. Percentages on different bases confuse; think dollars per contract.

Partial contracts

You cannot buy 0.3 contracts on standard US equity options. Size in whole contracts or use minis where listed.

Broker display settings

Some apps toggle per-share vs per-contract P/L. Match the setting to how you think before comparing to ThetaViz.

Spread multiplier is still per share

Net credit $1.20 on a two-leg spread is $120 per spread, not $1.20 total. Both legs share the 100 multiplier on standard equity options.

Related guides

• What are options
• Calls explained
• Reading payoff charts

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ThetaViz provides educational tools only. This guide is not investment, tax, or legal advice. Prices, margin requirements, and tax rules change. Confirm details with your broker and qualified professionals before trading.