Options Contract Calculator: Price and Greeks

VIX (volatility) 16.78

SOFR (interest rate) 3.87%

Load stock price →

// 01 Inputs

S Current stock price ?

Range: $1 – $100,000. Click SPY/QQQ above to auto-fill

⚠

K Strike Price (K) ?

ATM = close to S · ITM = Call below S / Put above S · OTM = the opposite

⚠

T Days to expiration (DTE) ?

days

Range: 1 – 1825 days · LEAPS contracts run past a year, up to about three years

⚠

σ Implied Volatility (IV) ?

⚠ The “← IV” button fills VIX (S&P 500 volatility), suited to SPY and SPX only. For single stocks use the stock's actual IV.

⚠

↺ Reverse · extract IV from the market price ?

r Risk-free interest rate ?

SOFR is now 3.87%. Use the "← r" button to fill it in automatically

⚠

Option type

Moneyness: --

// 02 Results CALL

Fair option price

OPTION PRICE (FAIR VALUE)

-- / contract ×100

Breakeven

BREAK-EVEN PRICE

// EM Expected Move ±1σ · ~68% over the period

± Expected Move

Expected range at expiration

± % move

The range the stock is expected to stay within ~68% of the time until expiration (one standard deviation; ±2σ ≈ 95%). A ruler for picking strikes for spreads and condors: selling the wings outside the range raises the probability of profit.

// SD × Δ Statistical link · Strike × probability SD × Delta Delta ≈ probability of ITM

Strike position (in σ)

Delta ≈ probability of ITM

Reading

The further the strike is from price in standard deviations, the lower the delta and the chance of finishing in the money (ITM): ATM ≈ delta 0.50 (~50%) · ~1σ ≈ 0.16 (~16%) · ~2σ ≈ 0.05 (~5%). Delta is an approximation of probability, not a guarantee. It helps you pick spread and condor strikes by the probability you want.

// 03 The Greeks

Delta

Price sensitivity per $1 change in the stock

Gamma

Rate of change of Delta per $1 move

Theta

Daily value decay (per share)

Vega

Sensitivity per 1% change in IV

Rho

Sensitivity per 1% change in rates

// 04 Stress test matrix ?

// 05 P&L at expiration

// 06 Theta Decay curve ?

Not sure which one to pick? My price view Implied Volatility

// 01 Bull Call Spread

Limited risk Limited gain Bullish

Buy a Call at a lower strike and sell a Call at a higher strike. The structure gains if the stock rises above breakeven · and its maximum loss is the net debit paid.

* Values are per share. For a full contract (100 shares): multiply × 100

// 02 BULL CALL SPREAD, P&L at expiration

Max profit

MAX PROFIT

per share

Max loss

MAX LOSS

per share

Breakeven

BREAKEVEN

Stock price

Reward / risk

Risk : Reward ratio RATIO

Per $1 of risk

// How this trade works

✓ Best case

✗ Worst case

// Trade legs · TRADE LEGS

Action	Type	Strike Price	Description	$/share

01 · Black-Scholes inputs: what do they mean?

Ticker	Name	Description	Example
S	Current stock price	The price the stock trades at in the market now	SPY = $542
K	Strike Price	The price at which the contract gives you the right to buy (Call) or sell (Put)	$545 or $540
T	Days to expiration (DTE)	Full days until the contract expires. The fewer there are, the faster time decay gets	7, 30 or 45 days
σ (IV)	Implied Volatility	The market's expectation of how far the stock will move. Use VIX as a general reference, or look up the stock's actual IV on your platform	VIX 18% → approx. IV
r	Risk-free interest rate	Secured Overnight Financing Rate (SOFR). It has a small effect on the price	SOFR ≈ 3.87%

02 · The Greeks: how do you read them?

Delta

Ranges from 0 to 1 for a Call option (or 0 and −1 for a put option ). Delta 0.60 means: if the stock rises $1, the option rises ~$0.60. ATM ≈ 0.50, ITM close to 1, OTM close to 0.

Gamma

Rate of change of Delta. High Gamma means Delta changes fast, more risk near expiration. Important for holders of short-term contracts.

Theta (time decay)

Always negative for an option buyer. Theta −0.05 means: the option loses ~$5 of its value each day (per contract × 100). Option sellers benefit from positive Theta.

Vega

Sensitivity to Implied Volatility. Vega 0.30 means: if IV rises 1%, the option rises $0.30. Vega is high in long-dated contracts.

Rho

Sensitivity to interest rates. Matters less than the other Greeks in most short-term trades. Has more effect on long-dated contracts (LEAPS).

03 · When does each strategy fit?

Strategy	Your market view	Risk	Gain	When?
Bull Call Spread	↑ Moderately bullish	Net Debit	K2 − K1 − Debit	You expect a rise but don't want to pay a high premium
Bear Put Spread	↓ Moderately bearish	Net Debit	K2 − K1 − Debit	You expect a drop at limited cost
Long Call	↑ Strongly bullish	Premium only	Unlimited	Before a big event (earnings, data) you expect a sharp rise
Long Put	↓ Strongly bearish	Premium only	K − P	To hedge or if you expect a crash
Iron Condor	→ Neutral	Wing − Credit	Net Credit	Quiet market, high IV → you sell volatility
Covered Call	→↑ Neutral / slightly bullish	Stock risk	Limited	You own the stock and want extra monthly income
Cash-Secured Put	→↑ Neutral / slightly bullish	K − P	Premium	You want to buy the stock at a lower price or collect premium

04 · Quick tips for traders

ATM vs OTM: A ATM Call (S ≈ K) has faster Theta decay, so choose the expiration carefully. OTM is cheaper but needs a bigger move.
Before earnings: IV spikes before the announcement and then collapses after it (IV Crush). Buying options before earnings is expensive; consider selling instead of buying if you expect the price to stay flat.
Timing for a bullish call: pick DTE 30–45 days. It balances time decay against giving the stock enough time to move.
Risk-to-reward ratio: A ratio below 1:1 rarely justifies a trade. 2:1 or more is stronger.
Contract × 100: each contract represents 100 shares; multiply the option price × 100 to get the actual cost in dollars.

Want to understand the Greeks in more depth?

The full Greeks reference (Delta · Gamma · Theta · Vega · Rho) with real examples

Full Greeks reference →

Options calculator FAQ

What is the Black-Scholes model and why use its calculator?

A mathematical model that estimates an option's theoretical value from five inputs: stock price, strike price, time left, volatility and the risk-free rate. Its use is not predicting price but comparing the market price with a reference value, and knowing the Greeks that come with the contract.

Why does the market price differ from the calculator's result?

Because the model assumes known, constant volatility, while the market prices a changing expectation. The gap sits mostly in Implied Volatility: enter higher volatility and the output rises. The model also assumes log-normal returns, while the market prices fatter tails than that.

Does the calculator work for American options?

Black-Scholes is built for European options, which are exercised only at expiration. In practice the gap is small for calls on stocks with no dividends, and grows for deep in-the-money puts and near the dividend date.

Which Implied Volatility did you enter?

The one shown on the options chain for the same contract, not the stock's historical volatility. Each strike and expiration has its own Implied Volatility, and that difference itself · <b>Volatility Skew</b> · is information, not an error: when it is higher on puts, it measures what the market pays to insure against a drop.

Why is the result multiplied by 100?

Because one contract covers 100 shares in the US market. A contract quoted at $2.35 actually costs you $235 before commissions. This is the first thing that surprises beginners on their statement.

Does the calculation run on my device or on the server?

The whole calculation runs in your browser. Your inputs are not sent to any server. That makes the result instant with every change, and keeps your account numbers with you.

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About this tool: Pricing & volatility calculator

What does it do?: Black-Scholes pricing with all the Greeks and the effect of Implied Volatility · calculated in your browser.
What do you get from it?: See whether a contract's price is reasonable and how time and volatility change it.
Who is it for?: Anyone buying an option; good for beginners because it explains each number.