"Das stimmt nicht ganz."

Translation: That is not exactly true.

[simleo]

I think "that is not entirely true" should be accepted as well

[niranjantdesai]

It is now accepted :)

[brtzsnr]

The suggested solution "That is not eactly true." is obviously incorrect.

[DoubleFelix]

It makes sense to me. "Das stimmt" = "that agrees", interpretable as "that fits" or "that is true", nicht=not and ganz=entirely.

So "Das stimmt nicht ganz" is "That does not entirely agree" or "that is not entirely true" or "that is not exactly true".

[Musetta]

I would suggest: "That is not quite true."

[Daniel.W.T]

''That'' is correct but ''This'' is wrong...

[wstoutamire]

"This" would be "Dies"

[DERGAUNER]

That is not correct or exact does not carry the same meaning as that is not true, nicht wahr ?

[TynHan16]

I think "that is not fully true" should also be accepted.

[taynie]

I wich "that is not exactly right" would also be right. couldn't decide if I should use true or right... since I believe on the contectst what you would like to use, or how you choose to express yourself.
In swedish we have a word "stämma" which I believe is equal to "stimmt" but we also have a word for right and true, so If you want to say "stämma" you have to choose which word to use...