わけだ

Phrase (Basic ㊦ 531)

The speaker's conclusion obtained through deductive, logical judgment or calculation on the basis of what he has heard or read.

Equivalent: No wonder; so it means that ~; that's why; should ~; I take it that ~; naturally

毎日三時間も日本語を勉強いるんですか。よく出来るわけですね。
Are you studying Japanese (as long as) three hours every day? No wonder your Japanese is good.
明日試験ですか。じゃあ今晩忙しいわけですね。
Do you have an exam tomorrow? Then, you must be busy tonight.
スミスさんは十年間もテニスをしたのだから上手なわけだ。
Mr. Smith has played tennis for ten years, so he should be good at it.
A:来月から四ヶ月フランスに行きます。  B:すると、六月に帰ってくるわけですね。
A: I'll go to France next month and stay there for four months.  B: Then, I take it that you're returning here in June?
毎日プールで泳いでいるんですか。丈夫なわけですね。
Are you swimming in the pool everyday? No wonder you're healthy.
昨日は三時間しか寝ていない。道理で眠いわけだ。
Yesterday I slept only three hours. No wonder I am sleepy.
えっ？足立さんが入院したんですか。パーティーに来なかったわけだ。
What? Was Mr. Adachi hospitalized? No wonder he didn't come to the party.
A:山田さんは英語のことは何でも知っています。  B:生き字引というわけですか。
A: Mr. Yamada knows everything about English.  B: You mean he is a living dictionary?
父の言うことが分からないわけではないが、どうしても医者になりたくない。
It is not that I don’t understand what my father is saying; I simply don’t want to become a medical doctor.

Formation

(i) {V/Adjective い} informal わけだ  
  {話す /話した} わけだ I take it that someone talks/talked
  {食べる /食べた} わけだ I take it that someone eats/ate
  {高い /高かった} わけだ I take it that something is/was expensive
(ii) Adjective な stem {な/だった} わけだ  
  {静かな/静かだった} わけだ I take it that something is/was quiet
(iii) Noun {という/だった} わけだ  
  {先生という/先生だった} わけだ I take it that someone is/was a teacher

Notes

1. わけ can be used as a full noun, meaning reason as in (1) and (2) below:

2. わけで is the て form of わけだ.

【Related Expression】

はずだ 'expect' is similar but not identical to わけだ. はずだ can express a speaker's expectation when there is no preceding context; わけだ cannot. In other words, わけだ is highly dependent on verbal context.

(⇨ はずだ)

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