Both grande and gran mean “big” or “great,” but they are used differently:

Grande → Used after a noun, meaning “big” in size.

✅ Un perro grande. (A big dog.)

✅ Una casa grande. (A big house.)

Gran → A shortened form of grande used before singular nouns, meaning “great” or “important.”

✅ Un gran hombre. (A great man.)

✅ Una gran idea. (A great idea.)

Think: Grande = big in size | Gran = great or important!