You use that's it to express agreement with or approval of what has just been said or done .
that's all
You can say that's all at the end of a sentence when you are explaining something and want to emphasize that nothing more happens or is the case .
that's life
People say ' That's life ' after an unlucky , unpleasant, or surprising event to show that they realize such events happen occasionally and must be accepted.
that's that
there is no more to be done, discussed , etc
that's better
You say ' That's better ' in order to express your approval of what someone has said or done , or to praise or encourage them.
that's enough!
You say ' that's enough ' to tell someone, especially a child, to stop behaving in a silly , noisy , or unpleasant way.
that's an idea
that is worth considering
that's done it
an exclamation of frustration when something is ruined
that's torn it
an unexpected event or circumstance has upset one's plans
that's as may be
that may be so
that's the shot
that is the right thing to do
that's the stuff
that is what is needed
that's the ticket!
that's the correct or proper thing! that's right!
and that's a fact
You say and that's a fact to emphasize the truth or correctness of a statement that you have just made.
that's all she wrote
said when there is no more to say or when something is finished
that's more like it
If you say that's more like it , you mean that the thing that you are referring to is more satisfactory than it was on earlier occasions .
but that's another story
You say ' but that's another story ' when you have mentioned a subject that you are not going to talk about or explain in detail .
that's the way the cookie crumbles
said to mean that you should accept the way that things happen , even if it is bad
that's the end of the matter/that's an end to the matter
If someone says that's the end of the matter or that's an end to the matter , they mean that a decision that has been taken must not be changed or discussed any more.