Multi-Leg Greeks Calculator

A single option's Greeks tell you how that one contract behaves. Once you're running a real position with multiple legs, what matters is how they add up together, since a long call and a short call at different strikes don't cancel out evenly. This calculator sums Delta, Gamma, Theta, Vega, and Rho across an entire multi-leg position, up to 4 legs, the same way a trading desk actually reads a position's risk.

It uses the same engine as this site's Black-Scholes Option Pricing Calculator, just applied to every leg and combined with the correct sign for long versus short. If you're not sure what volatility to enter, the Implied Volatility Calculator can back it out from a quoted option price.

How does this calculator work?

Enter the current price, an implied volatility assumption, days to expiration, and the risk-free rate. These four inputs are shared by every leg, since this calculator assumes one underlying and one expiration for the whole position (see the FAQ below on calendar spreads).

Add each leg: long or short, call or put, strike, and number of contracts. Up to 4 legs are supported, enough for most common multi-leg structures (spreads, condors, butterflies, and so on).

For each leg, the calculator runs the same Black-Scholes Greeks formulas used by the single-option calculator, producing per-share Delta, Gamma, Theta, Vega, and Rho.

Each leg's per-share Greeks are then scaled up to dollar or share terms by contract size (100 shares per contract × number of contracts), and by sign: long legs add their scaled Greeks to the running total, short legs subtract them, since a short position's exposure runs opposite to a long one.

The five position-level totals shown at the top are just those signed, scaled contributions added across every leg you entered, and the per-leg table below breaks out exactly how much each individual leg contributed to each total. A chart also plots position delta across a range of underlying prices (60% to 140% of your current price), so you can see how the position's exposure shifts as the underlying moves, not just at today's price.

For a deeper dive into what each Greek means individually, see Britannica Money's option Greeks explainer or Option Alpha's guide.

Worked example

A bull call spread: long 1 contract of the $100 call, short 1 contract of the $110 call, on a $100 stock at 25% implied volatility with 30 days to expiration.

Position delta

≈42.9 shares

Position theta

≈-$3.08/day

Position vega

≈$6.06 per 1-point vol move

How the numbers work

The long $100 call alone would have a much higher delta on its own, but the short $110 call offsets part of it, leaving the spread behaving like about 43 shares of stock rather than 100.

Because both legs are long-dated calls with time value, the spread still loses money to time decay overall (negative theta), though less than the long call alone would, since the short call's decay works in the position's favor.

Portfolio Greeks reveal risk that isn't obvious from looking at each leg separately. A position can look aggressive leg-by-leg but behave modestly once combined, or the reverse, which is exactly why traders check combined Greeks before and during a multi-leg trade rather than relying on intuition.