とすれば / としたら / とすると

The expressions とすれば, としたら, and とすると are used to introduce a hypothetical assumption and then discuss its consequences or implications. They mean "if we assume that…", "supposing that…", or "if it turns out that…". All three are formed from the quotative と + する ("to assume/suppose") conjugated into different conditional forms.

Basic Usage

These expressions attach to the plain form of verbs, adjectives, and nouns (+ だ):

Nuance Differences

While the three forms are largely interchangeable, they carry slightly different nuances:

• とすれば – tends to sound more logical and analytical. Often used when reasoning through a situation step by step.

  ひとり一人ごせんえん5000円だとすれば、ぜんぶ全部でにまんえん2万円かかる。

  If we assume it's 5,000 yen per person, it'll cost 20,000 yen in total.

• としたら – the most conversational and common of the three. Frequently used for imaginative or counterfactual hypotheticals.

  もういちど一度やりなおせるやり直せるとしたら、どうしますか。

  If you could start over, what would you do?

• とすると – often used to draw a conclusion from information just received or stated. It carries a nuance of "if that's the case, then…".

  でんしゃ電車がとまっている止まっているとすると、ばすバスでいく行くしかない。

  If the trains have stopped, we have no choice but to go by bus.

Common Patterns

These forms are often preceded by もし to emphasize the hypothetical nature of the assumption:

They are also common with noun + だ to set up a premise: