ぐらい・くらい
about (an amount)
Amount + ぐらい / くらい
Sign up free to review this point on a spaced schedule.
ぐらい (or くらい, which is the same word) after an amount means "about" or "roughly": 十分ぐらいかかります, "it takes about ten minutes"; 二十人ぐらい来ました, "about twenty people came".
どのぐらい asks "how long", "how far" or "how much": 駅までどのぐらいかかりますか.
Compare ごろ, the next point. ごろ is "around" a point in time (三時ごろ, around three o'clock); ぐらい is "about" an amount (三時間ぐらい, about three hours). You'll hear ぐらい used for clock times too in casual speech, but keeping them apart is the safe habit.
Examples
駅まで十分ぐらいかかります。
It takes about ten minutes to the station.
毎日二時間ぐらい勉強します。
I study for about two hours a day.
パーティーには二十人ぐらい来ました。
About twenty people came to the party.
東京から大阪までどのぐらいかかりますか。
How long does it take from Tokyo to Osaka?
このかばんは五千円ぐらいでした。
This bag was about 5,000 yen.