Idioms and Phrases with that's right
Yes; that's correct; I agree. For example, Are you leaving early?—That's right, I have to go now, or So you were classmates?—That's right. [c. 1900]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.