You shouldn't simply memorize the Korean particles 마다 and 씩 as the English words “each” or “every.” Let's understand what they mean through examples.
1. with a number
마다
: The quantity indicates an interval or a reference point, and the action is repeated at each interval.
씩
: The action is done with that quantity at a time.
30분마다 운동해요.
I exercise every 30 minutes.
30분씩 운동해요.
I exercise for 30 minutes at a time. (I work out for 30 minutes each time.)
네 명씩 앉으세요.
Please sit four people at a time. (Please sit in groups of four. )
한 사람마다 두 개씩 가져가세요.
Please take two per person.
두 사람마다 한 개씩 가져가세요.
Please take one for every two people.
2. with a noun that is not a number
마다
: It is similar to meaning 1. The action is repeated for each noun.
씩
: It combines only with number nouns.
아침마다 운동을 해요.
I exercise every morning.
일요일마다 교회에 가요.
I go to church every Sunday.
집집마다 에어컨이 있어요.
Every house has an air conditioner.
사람마다 달라요.
It’s different for each person.