Have or Have Got

People aren’t always sure when they should use have or have got. When you want to talk about possession[1], they can be used in the same way. Just like we use has for the third person singular, we use has got for the third person singular too. While we use have or have got for all the other persons. 

I have a problem. = I have got a problem.
He has a problem. = He has got problem.

As you can see, it’s just a question of preference. But there are a couple of things to keep in mind.

1) In have got, have acts as an auxiliary verb. So we use have as the auxiliary verb in questions and with not in negative phrases. For example:

Have you got a problem?
I haven’t got a problem.

Whereas with just have, you need to use another auxiliary verb, like do in the present simple. For example: 
Do you have a problem?

I don’t have a problem.


2) Have got, when used for possession, can only be used in the present simple. For all other tenses, you have to use have. Some examples: 

I have got a problem. / I have a problem. (present simple) 

I am having a problem. (present continuous) 

I had a problem. (past simple) 

I have had a problem. (present perfect) 

I will have a problem. (future simple)

We can also use have to and have got to in the same way to talk about obligations[2]:

They have to go home. = They’ve got to go home

3) Then there are expressions where we only use have.

I have a shower every morning. = I take a shower every morning.

I have got a shower. = There is a shower in my home.

I have dinner at 8 o’clock at night. = I usually eat dinner at 8:00. 

I’ve got a dinner at 8 o’clock at night. = I have a dinner date tonight. 


Here are more examples:

She's having a baby. = She's giving birth.
We have a drink together. = We often drink something together. 
We have a cigarette aftert lunch. = We smoke after lunch. 

Have fun tonight! Have a good time! Have a ball! = Enjoy the night! 

Have you got the gist[3] of it? Now you can have a go at[4] it!

[1] tener, [2] tener que, [3] captar lo esencial de, [4] probar