Grammar - difference 3

study ex 1 ex 2 ex 3 ex 4
 

Use: future simple: will

Use: to be + going to

Instant decision (=when we decide
to do something at the time of speaking).

I will have a cup of coffee.

Intention
(=the speaker has already decided before).
I am going to have a cup of coffee.
   

I will operate my patient again.

I am going to operate my patient.
   
   

Prediction
(= what we think will happen).

He will travel to Ireland.

Prediction based on a present situation
(=what we can see is going to happen).

He is going to travel to Ireland.
   

He will hit the ball.

He is going to kick the ball.