にすぎない is a common structure in Japanese used for indicating that something is ‘no more than (A)’, or ‘merely (A)’. This expression is constructed from に, and the negated form of the る-Verb 過（す）ぎる, meaning ‘to exceed’, or ‘to be more than’. Due to this, the literal translation of ‘to not be more than (A)’ reflects the English interpretations closely.
にすぎない is slightly formal, but is heard fairly often in day-to-day speech as well. This grammar pattern may be used after verbs in any of their standard forms, い-Adjectives, な-Adjectives, or nouns.

• 私（わたし）はお金（かね）が欲（ほ）しかったから、あなたを助（たす）けたにすぎない。
  I helped you just because I wanted money.
• どんだけ勉強（べんきょう）していても、ちゃんと集中（しゅうちゅう）して勉強（べんきょう）をしないと時間（じかん）を無駄（むだ）にしているにすぎない。
  No matter how much you study, if you don't focus on your studies properly, you are just wasting your time.
• あの建物（たてもの）は古（ふる）いだけにすぎない。
  That building is nothing more than old.
• 田中（たなか）さんはハンサムなだけにすぎない。
  Tanaka-san is nothing more than handsome.
• 藤田（ふじた）さん、君（きみ）は子供（こども）にすぎない。
  Fujita-san, you are nothing more than a child.

にすぎない is often seen paired with structures that will emphasize the phrase even further, such as ただ ‘merely’ or だけ ‘just’. In the case of だけ, it will come between the target word and にすぎない. Also, standard conjugation rules will need to be remembered, such as adding な after a な-Adjective before だけ.

• この納豆（なっとう）はただくさいだけにすぎない。
  This natto just smells.
• 田舎（いなか）はただ不便（ふべん）なだけにすぎない。
  The countryside is nothing more than inconvenient.