Options calculator
Price any call or put both ways: American-style (binomial tree — how US equity options actually trade) or European-style (Black-Scholes). Theoretical value, all five Greeks, breakeven, early-exercise premium, and how your P/L evolves across price and time — recalculated as you type.
Educational tool, not advice. American pricing uses a 400-step Cox-Ross-Rubinstein binomial tree; European uses Black-Scholes. Both are theoretical models — real quotes include spreads and the market's own opinions. Garbage IV in, garbage price out.
| Price | +0d | +6d | +12d | +18d | +24d | EXPIRY |
|---|---|---|---|---|---|---|
| $118 +18% | $1,160 | $1,124 | $1,090 | $1,060 | $1,038 | $1,029 |
| $115 +15% | $908 | $865 | $824 | $781 | $744 | $729 |
| $112 +12% | $676 | $627 | $576 | $519 | $463 | $429 |
| $109 +9% | $465 | $413 | $354 | $288 | $209 | $129 |
| $106 +6% | $281 | $227 | $166 | $95 | $2 | -$171 |
| $103 +3% | $126 | $73 | $13 | -$54 | -$141 | -$271 |
| $100 0% | -$1 | -$48 | -$98 | -$157 | -$222 | -$271 |
| $97 -3% | -$96 | -$134 | -$177 | -$219 | -$257 | -$271 |
| $94 -6% | -$164 | -$195 | -$224 | -$250 | -$268 | -$271 |
| $91 -9% | -$211 | -$232 | -$251 | -$264 | -$271 | -$271 |
| $88 -12% | -$240 | -$253 | -$263 | -$269 | -$271 | -$271 |
| $85 -15% | -$256 | -$264 | -$268 | -$271 | -$271 | -$271 |
| $82 -18% | -$265 | -$268 | -$270 | -$271 | -$271 | -$271 |
// how to use this thing
Enter the stock price, strike, days to expiration and implied volatility (grab IV from your broker's option chain). The calculator returns the theoretical premium — if you already own the option, type the price you actually paid and every P/L number anchors to your real fill instead.
// what the greeks mean, quickly
- Delta — how much the option moves per $1 stock move (also a rough probability of expiring in the money).
- Gamma — how fast delta itself changes; peaks at-the-money near expiration.
- Theta — what one day of time decay costs you (or pays you, if short).
- Vega — P/L per 1% change in implied volatility. The IV-crush dial.
- Rho — sensitivity to interest rates. The one everyone ignores until rates move.
New to options entirely? Read what are options and what is implied volatility on the Press first — this page makes 10× more sense afterward.
// american vs european — which to pick?
US-listed equity options are American-style: you can exercise any day up to expiration, so that's the default here. European options (most index options, like SPX) can only be exercised at expiration. The gap between the two prices — shown as the early-exercise premium — is usually near zero for calls on non-dividend stocks (early exercise is rarely optimal) and largest for deep in-the-money puts and calls on big dividend payers. When the premium reads ≈ $0.00, the models agree and Black-Scholes was fine all along.
// reading the matrix
Each cell is your position's profit or loss if the stock lands at that price (rows) on that date (columns). Watch the green fade as columns move right while the stock stands still — that's theta, charging rent daily. The final column is expiration: pure intrinsic value, no time premium left to bill.