Options price can be influenced by a number of factors which are called the Options Greek. They are Delta, Theta, Vega and Gamma.  Before getting started trading options, you might want to understand how these factors can change the optios characteristics. 

Delta: 

The ratio of the change of the underlying asset’s price to the change of the call or put options.

It is from the range of 0.00 to 1.00. For example, if the delta is +0.50, which refers to every $1 movement of the stock, your call options premium will be increased $0.50.  

On the hand, for put options delta will be negative, let say delta is -0.50, every $1 increase in the underlying stock, there will be $0.50 decrease for your put options premium. As the In-The-Money call/put options near its expiration, the delta will become +1 or -1 respectively.

Delta is very sensitive to Time and Volatility especially ITM or OTM option, ATM option will be immuned to these two factors. Both ATM Options that is 60 days to expiration and 10 days to expiration have the delta of close to 0.50.  

Theta: 

Theta is the rate of decline in options premium regards to the time remaining. Options value will be decreased as the time value decrease, Theta is the measure for the time value. Therefore remember, Theta related to Time. (T for time) 

For example, if Theta is 0.05, it means everyday the options premium will be drop $0.05 each day. Options premium will drop like waterfall when it comes to expiration, therefore Theta will be increased when it near the options’ expiry date. 

Theta will be highest for ATM option because it has the most extrinsic value than ITM or OTM options. 

Gamma: 

Gamma is the measure of rate of change in delta, similar to acceleration when talking about speed. It tells you how much the delta change when the stock price moves $1.00. Gamma will be largest only when the options is near the money. 

Gamma basically is telling how stable is the delta, if Gamma is close to 0, the change of delta is gradual. If Gamma is big, it means a small move of the underlying asset can cause a significant change of the options premium. 

Vega: 

Vega is related to Volatility (V for Volatility). Vega tell us the change of the options premium as the implied volatity change 1.00%.  

Options premium is very much influenced by the volatility of the underlying asset, if the volatility is high, options premium will be increased, when the underlying asset is stable - no volatility, options premium is cheap. With this characteristic, options seller always benefited from the implied volatily drop as the options premium will be decreased tremendously.

For example, ABC Call option has implied volatility of 40%, vega 0.1, and its premium is $1.00. When its IV (Implied volatility move to 41%, the option premium will increase to $1.1 now.  

How to read the Greek Table: 

I will show you an example here to understand the Greek number here in the Interactive Broker format:

QQQQ is trading at 29.5 level, which means that 29 Call is ITM (in the money) and 30 is near OTM (out the money). 

I have used eight examples - 25, 29, 30 and 35 options with Dec 31 and Jan 16 expiration options.

1. Delta - Delta is the highest when Options is deeper In-the-money and become less when it is further Out-of-the-money. Put Options has minus delta. 25 Call has Delta of 0.97 but 35 Call only has Delta of 0.0244 in this example. Therefore, for 29 Call option (Dec) which is +0.5919, the premium will be increased if QQQQ moves up to $30.5 from the current $29.5. 

2. Gamma - 29 Option has the highest Gamma because delta change the most when it is ATM. Gamma become smaller when it is ITM and OTM, which means the delta change will be smaller than ATM option. 

3. Vega - 29 Option has the highest Vega as believe that At the money has the highest volatity. Use the same example of 29 Call Option (Dec), Vega is 0.016 , current IV is 40.52%, if IV increase to 41.52%, the premium will be $0.87 + $0.016 = $0.886. 

4. Theta - Jan options has longer time before expiration, therefore Theta for Jan options is smaller than Dec options.