How to say "twice" in Japanese

• 倍ばいJLPT N4approx.Common
  no-adjectiveCovers 'twice' meaning 'twice as much': a doubled amount, size or degree, not two separate occurrences. Use it when a quantity doubles — paying, earning or holding twice as much as before.
  彼かれは私の倍ばい食たべた。↗

  He ate twice as much as I did.
• 二回にかいCommon
  no-adjectiveThe plain counting word for 'twice': two occurrences of an event, as in visiting, calling or meeting someone twice, or twice a week. Neutral, and it works wherever you simply count how many times.
  私は「スターウォーズ」を２回かい見みたことがあります。↗

  I have seen "Star Wars" twice.
• 二度にどCommon
  nounAlso means 'two times; twice' and largely overlaps with 二回 in counting occurrences; for a plain statement that something happened twice, either word is normally fine. It does not express 'twice as much'.
  １度いちどや２度どの失敗しっぱいはだれにでもある。↗

  Everybody fails once or twice.
• 再度さいどCommon
  adverb, nounIts core sense is 'again; a second time; once more'; it fits 'twice' only when that means doing something a second time, as in repeating an attempt, not for counting two plain occurrences.
  それから、それが適切てきせつであることを確認かくにんするために再度さいど見直みなおした。↗

  Then he went back over it to make sure it was right.

Use 倍 for 'twice as much', a doubled amount; 二回 or 二度 for counting two occurrences; and 再度 only when 'twice' means doing something a second time or again.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 倍ばいdouble
• 二回にかいtwice
• 二度にどtwo times
• 再度さいどa second time
• 二倍にばいdouble
• 一倍いちばいdouble