얼마나 + adjective: 얼마나 걸려요?, 얼마나 커요?
how (much, long, far); how very
Example
집에서 학교까지 얼마나 걸려요?
How long does it take from home to school?
Word parts
얼마 (how much) + 나.
Good to know
얼마예요? asks a price; 얼마나 asks degree: 얼마나 걸려요? = How long does it take?
Related words