To the point of: 〜くらい・〜ぐらい

At N5, くらい / ぐらい meant “about”. It's also used to express a degree: “to the point of, so… that” (泣きたいくらい痛い). With これ, それ or a noun, it can play things down: “at least that, something so small” (これくらい自分でできる). くらい and ぐらい are used interchangeably.

• 泣きたいくらい痛かった。なきたいくらいいたかった。It hurt so much I could have cried.
• 歩けないくらい疲れた。あるけないくらいつかれた。I was so tired I couldn't walk.
• これくらい、自分でできるよ。これくらい、じぶんでできるよ。I can do something like this on my own, you know.
• 京都から東京まで、どれくらいかかりますか。きょうとからとうきょうまで、どれくらいかかりますか。How long does it take to get from Kyoto to Tokyo?

くらい measures a quantity, but also an intensity. Placed after a clause, it gives a picture of the degree reached: “so tired I couldn't walk”, “so good you want more” — English “so… that”, “to the point where”.

It's a very lively tool in speech: you pick an exaggerated image to convey the intensity.

• このお茶は、毎日飲みたいくらいおいしい。このおちゃは、まいにちのみたいくらいおいしい。This tea is so good I'd like to drink it every day.
• 京都の夏は、外に出たくないぐらい暑い。きょうとのなつは、そとにでたくないぐらいあつい。Kyoto summers are so hot you don't feel like going out.

くらい (or ぐらい) follows a verb or an adjective in the plain form, a noun, or これ・それ・あれ・どれ. Both pronunciations are correct; after a noun, ぐらい is slightly more common.

• 駅まで十分ぐらいです。えきまでじっぷんぐらいです。It's about ten minutes to the station.
• 日本語の本が読めるくらいになりたい。にほんごのほんがよめるくらいになりたい。I'd like to reach the point where I can read books in Japanese.

With a noun or これ・それ, くらい can play things down: the thing is easy, small, obvious. You often hear it in reproaches: 電話くらいしてよ (“you could at least call!”).

• 遅くなるなら、電話くらいしてよ。おそくなるなら、でんわくらいしてよ。If you're going to be late, you could at least call!
• 自分の部屋ぐらい、自分で片付けなさい。じぶんのへやぐらい、じぶんでかたづけなさい。Your room, at least, tidy it yourself!

ほど (next point) also expresses degree, but in a more formal register, and is never used to play things down. ごろ only indicates an approximate time: 三時ごろ (around three o'clock), whereas 三時間ぐらい means “about three hours (duration)”.