だとしたら

だとしたら
expression
if that is so; supposing that
grammatical
1. if that is the case; supposing (it is) that
A conditional built from the copula だ + としたら. At the start of a sentence it takes up what was just said ("if that's true, then…"); after a noun or a plain clause it sets up a supposition ("supposing it is ~"), and the speaker goes on to draw a conclusion or ask a question.
だとしたら、大変(たいへん)だ。
If that's true, we're in trouble.
彼(かれ)が犯人(はんにん)だとしたら、動機(どうき)は何(なん)だろう。
Supposing he is the culprit, what would his motive be?
「明日(あした)は雨(あめ)らしいよ」「だとしたら、ピクニックは来週(らいしゅう)にしたほうがいいね」
"Looks like it'll rain tomorrow." "In that case we'd better move the picnic to next week."

Common patterns

  • だとしたら、〜: if that's so, then ~ (sentence-initial, reacting to what was said)
  • [noun / clause]だとしたら: supposing it is ~

Similar words

  • だとすれば: nearly the same, slightly more logical and written in tone
  • それなら / なら: if so; more casual, and なら also covers advice and choices
  • そうだとしたら: the fuller form of the sentence-initial use

Related Words

Compare: それなら (if so)
general
Added 2026.10.13 4:28 · Revised 2026.10.13 4:29
31500/31967_datoshitara