"Comprise" = the whole includes the parts; "compose" = the parts make up the whole.
The whole "comprises" its parts: the whole is the subject, the parts are the object. Always from the general to the specific.
The United States comprises fifty states and one federal district.
The committee comprises twelve members from different departments.
The collection comprises over three hundred paintings from the Renaissance.
The parts "compose" the whole: the parts are the subject, the whole is the object. From the specific to the general.
Fifty states and one federal district compose the United States.
Twelve members from different departments compose the committee.
Water molecules are composed of two hydrogen atoms and one oxygen atom.
Common mistake
"Is comprised of" is technically incorrect but so ubiquitous that many dictionaries now accept it. The prescriptive use: "The US comprises fifty states" (NOT "is comprised of fifty states") = "Fifty states compose the US" = "The US is composed of fifty states". The confusion is so universal that even advanced native writers make it.
Trick to remember it
The inclusion rule: the WHOLE comprises (includes) its PARTS. The PARTS compose (make up) the WHOLE. Quick test: substitute "comprises" with "includes" — if it works, you are fine. "The US includes fifty states" — yes. "Fifty states include the US" — no, so the parts "compose", not "comprise", the whole.
Quick rule
The whole COMPRISES the parts. The parts COMPOSE the whole. Never: "comprised of" (though now widely accepted).
Did you know?
"Is comprised of" appears in legal documents, prestigious newspapers, and presidential speeches — and has since the 19th century. Despite being prescriptively "wrong", the battle is almost lost for the purists.
Exercise 1 · Pick the right one
The solar system _____ eight planets, dozens of moons, and millions of asteroids.
Exercise 2 · Pick the right one
Eight planets, dozens of moons, and millions of asteroids _____ the solar system.
Exercise 3 · Form the word
The whole COMPRISES the parts. The parts COMPOSE the whole. Never: "comprised of" (though now widely accepted).
"Is comprised of" is technically incorrect but so ubiquitous that many dictionaries now accept it. The prescriptive use: "The US comprises fifty states" (NOT "is comprised of fifty states") = "Fifty states compose the US" = "The US is composed of fifty states". The confusion is so universal that even advanced native writers make it.
The inclusion rule: the WHOLE comprises (includes) its PARTS. The PARTS compose (make up) the WHOLE. Quick test: substitute "comprises" with "includes" — if it works, you are fine. "The US includes fifty states" — yes. "Fifty states include the US" — no, so the parts "compose", not "comprise", the whole.
Bryan López
Founder of SpeakUP Academy