I've Already Had - I Already Have?

I've already had one.
or
I have already had one.
or
I have had one already.
or
I've had one already.

Actually, you haven't described the context completely, but I can fill that in for you.

A: Do you want a cup of coffee?
(B has a cup of coffee right in front of him.)
B: No, thanks. I already have one.

A: Do you want a cup of coffee?
(B is not drinking anything at the moment. However, earlier he drank some coffee.)
B: No, thanks. I've already had one.

CJ

Yes, good point Jim, I didn't think of the first scenario.

No, thanks. I already have one.

There's still a little problem with this:

A: Do you want a cup of coffee?
(B has a cup of coffee right in front of him.)
B: No, thanks. I already have one.
(Correct - Present Simple tense)

A: Do you want a cup of coffee?
(B is not drinking anything at the moment. However, earlier he drank some coffee.)
B: No, thanks. I already had one.
(Was incorrect, is correct now - Past simple tense)

A: Do you want a cup of coffee?
(B is not drinking anything at the moment. However, earlier he drank some coffee and will probably drink some more soon.)
B: No, thanks. I've already had one.
(Is correct because it brings the past into the present - Present Perfect Tense)

The difference here was between the past simple and the present perfect.

AnonymousHowever, earlier he drank some coffee and will probably drink some more soon.

The use of the present perfect does not imply that the action described will probably happen again soon, if that's what you're trying to illustrate.

CJ

Why "I've"?

AnonymousWhy "I've"?

I've = I have

CJ