Grammar JLPT Level N3 - Lesson 14

Structure of は～くらいです:

は + Verb + くらい ⁽¹⁾ + だ
は + ［い］Adjective + くらい ⁽¹⁾ + だ
は + ［な］Adjective + な + くらい ⁽¹⁾ + だ
は + Noun + くらい ⁽¹⁾ + だ

⁽¹⁾ ぐらい

Details about は～くらいです:

は～くらいです is an expression in Japanese used to convey that '(B) is all that exists within (A)'. As with other grammar points that use くらい, this nuance will be shown in the form of an 'extent'. In は～くらいです, both は and くらい are being used as adverbial particles. This structure is often translated as '(B) is about the extent of (A)'.
To use this grammar pattern, (A) will come before は, highlighting the situation, place, thing, or person within which a limit exists. The (B) part of the sentence will then describe what that limit is, followed by くらいです (or だ).

休日(きゅうじつ)の日(ひ)に家(いえ)を出(で)るのは、買(か)い物(もの)に行(い)くときくらいです。
Going out to go shopping is about the only thing I do when I have a day off.
仕事(しごと)で忙しいのは、月曜日(げつようび)ぐらいだけです。
Monday is about the only time I am busy at work.
私(わたし)は基本的(きほんてき)になんでも食(た)べられますよ。食(た)べ物(もの)で嫌(きら)いなのは茹(ゆ)で玉子(たまご)ぐらいです。
In general, I can eat anything. Boiled eggs are about the only thing I dislike in regards of food.
私(わたし)の夢(ゆめ)は家族(かぞく)を作(つく)ることぐらいかな。
Starting a family is about the extent of my dreams.

In order to add extra emphasis, のもの or なもの may follow くらい.

距離(きょり)は5キロくらいのものです。
The distance is only about 5km.
電車(でんしゃ)は仕事(しごと)に行(い)くときに使(つか)っているくらいなものです。プライベートでは車(くるま)しか使(つか)いません。
Commuting to work is about the only time I use the train. In my personal time, I only use my car.