How Delta Moves A Call Option Value

How to use this example

• Start with the defaults: a $100 stock, a call worth $4.00, and a delta of 0.50.
• Drag the stock price. The call moves by stock change × delta — a $5 rise at delta 0.50 adds about $2.50 to the call, taking it from $4.00 to $6.50.
• Remember the ×100 rule: +$2.50 per share is about +$250 on one contract.
• Now try delta 0.20 and delta 0.80. Same $5 stock move, but the call changes by about $1.00 versus $4.00.

What delta means, in plain English

Delta estimates how much an option's price changes when the underlying stock moves $1. A call's delta runs from 0 to 1: close to 0 when it is far out of the money, about 0.50 at the money, and approaching 1 when it is deep in the money.

This page holds delta constant so the arithmetic stays simple. In real markets delta itself shifts as the stock moves, as time passes, and as implied volatility changes — so treat the result as a close estimate for small moves, not a promise.

Keep learning

Head back to the Basics lesson, or move on to real-number examples of long calls, long puts, and covered calls.