だけのことはある details
no wonder; that explains it — X fully lives up to what one would expect
フルマラソンでも余裕だね。三年間も毎日走っていただけのことはあるよ。
furu marason demo yoyuu da ne. sannenkan mo mainichi hashitte ita dake no koto wa aru yo.
Even a full marathon is easy for you. No wonder — you ran every day for three years straight. casual
準備に半年もかけただけのことはあって、発表は完璧だった。
junbi ni hantoshi mo kaketa dake no koto wa atte, happyou wa kanpeki datta.
Having spent half a year on preparation really showed — the presentation was flawless. neutral
- past
- polite
Examples
no wonder; that explains it — a stated cause or history fully justifies an impressive result
フルマラソンでも余裕だね。三年間も毎日走っていただけのことはあるよ。
furu marason demo yoyuu da ne. sannenkan mo mainichi hashitte ita dake no koto wa aru yo.
Even a full marathon is easy for you. No wonder — you ran every day for three years straight. casual
準備に半年もかけただけのことはあって、発表は完璧だった。
junbi ni hantoshi mo kaketa dake no koto wa atte, happyou wa kanpeki datta.
Having spent half a year on preparation really showed — the presentation was flawless. neutral
さすが田中先生、十年この分野を研究されてきただけのことはあり、ご説明が非常にわかりやすいです。
sasuga tanaka sensei, juunen kono bun'ya o kenkyuu sarete kita dake no koto wa ari, go setsumei ga hijou ni wakariyasui desu.
As one would expect of Professor Tanaka, after ten years of research in this field, the explanation is extremely clear. formal
Formation
plain clause + だけのことはあるattaches to plain clause{N}だけのことはあるattaches to noun
Notes
clause before だけ carries its own tense — most often た, but not required.
Related patterns
Similar
だけあって sits inside a sentence as a subordinate clause that still needs its own main predicate (プロだけあって仕事が速い); だけのことはある promotes the same admiring verdict to the sentence's OWN predicate — わざわざ来ただけのことはある needs nothing further, the judgment IS the sentence.
The same payoff seen from opposite ends — かいがある looks FORWARD from the effort to what it bought (練習したかいがあって優勝した), だけのことはある looks BACK from the result to whatever earned it, and that cause need not be an effort at all (元プロだけのことはある), where かいがある demands one.
だけのことはある judges a specific person or thing as living up to a known reputation or effort, and stays admiring (三年勉強しただけのことはある); のも当然だ judges a REACTION as unsurprising given the circumstances, with no admiration required — 怒るのも当然だ excuses anger, something だけのことはある could never do.
Lookalikes
Both end in こと＋は＋ある／ない, but they answer different questions — ことはない tells you an ACT is unnecessary (謝ることはない, "no need to apologize"); だけのことはある tells you a RESULT was earned (三年勉強しただけのことはある, "it shows he studied three years") — matching them by their shared tail reverses the point of the sentence.