くらい indicates an approximate amount
Japanese
ここから家までは10分くらいです。
English
It's about 10 minutes from here to my house.
Japanese
1年くらい日本語を勉強しています
English
I have been studying Japanese for about a year.
くらい indicates a comparison
Japanese
どのくらいの大きさですか?
English
What size is it?