As a combination of the 格助詞（かくじょし） (case marking particle) と, the 名詞（めいし） 同（おな）じ ‘the same’, and the 副助詞（ふくじょし） (adverbial particle) くらい. と同（おな）じくらい is an expression used to highlight that something is ‘about the same as (A)’.
To use と同（おな）じくらい, attach it to the end of a noun that you want to highlight as being the prime example, with whatever is comparable to it coming later in the sentence, or directly attached through the 格助詞（かくじょし） の.

• 彼（かれ）のパソコンはプリンターと同（おな）じぐらい大（おお）きい。
  His computer is as big as his printer.
• 先生（せんせい）、昨日（きのう）と同（おな）じぐらい痛（いた）いです。
  Doctor, it hurts about the same as yesterday.
• あの人（ひと）は車（くるま）と同（おな）じぐらいのスピードで走（はし）れる。
  He can run at about the same speed as a car.
• 今（いま）飼（か）っている犬（いぬ）と同（おな）じぐらいのサイズのワンチャンが欲（ほ）しいです。
  I want a puppy that is about the same size as the one I have now.

If you want to express that an action is being performed in ‘almost the same way’ as (A), に may replace の, after くらい.

• 値段（ねだん）が同（おな）じぐらいになるのなら、もっといいのを買（か）います。
  If the price is going to be about the same, I will buy the better one.
• あの女（おんな）の人（ひと）はお母（かあ）さんと同（おな）じぐらいに見（み）えたけど、年齢（ねんれい）を聞（き）いたらお祖母（ばあ）ちゃんと同（おな）い年（どし）だった。
  That lady looked about the same age as my mother, but when I asked her her, she was the same age as my grandma.