calm down vs settle down

calm down and settle down both are verbs.

Word	Noun	Adjective	Verb	Adverb
calm down	No	No	Yes	No
settle down	No	No	Yes	No

As verbs, calm down and settle down are synonyms defined as:

calm down and settle down: become quiet or calm, especially after a state of agitation

Other synonyms of calm down include calm, chill out, cool it, cool off, simmer down.

calm down (verb)	settle down (verb)
become quiet or less intensive	become settled or established and stable in one's residence or life style
make calm or still	become quiet or calm, especially after a state of agitation
become quiet or calm, especially after a state of agitation	settle into a position, usually on a surface or ground