すると

す

る

と

Common wordJLPTN4Freq.FrequencyTop 10,000

Meanings

1

conjunction

Indicates a natural consequence or next action in a sequence. Often used in narratives or when describing a chain of events.

角かど

を

曲ま

がっ

た

。

する

と

、

目め

の

前まえ

に

海うみ

が

広ひろ

がっ

た

。

I turned the corner. Then the sea spread out before my eyes.

2

conjunction

Used to draw a conclusion or ask a question based on what was just said. Similar to 'if that's the case' or 'so then'.

「明日あしたは休やすみだよ。」「すると、映えい画がに行いけるね。」
"Tomorrow is a day off." "In that case, we can go to the movies."

そうすると
More explicitly refers to the preceding statement ('if that is the case'), while すると can also simply mean 'and then' in a narrative sequence.
それなら
Similar to sense 2 of すると, but それなら is more colloquial and directly means 'if that's the case'.

Derived from the verb する (to do) in its conjunctive form し plus the particle と (when/if), literally 'upon doing'. Grammaticalized into a conjunction.