How to say "probably" in Japanese

• 多分たぶんJLPT N5approx.Common
  adverbThe default word for plain uncertainty, with no strong confidence either way; its range runs from 'probably' down to a softer 'perhaps' or 'maybe'.
  君きみにはたぶんみんなわかっていることでしょう。↗

  I expect you know all about it.
• おそらくJLPT N3approx.Common
  adverbUse this when you are fairly confident — 'most likely', 'in all likelihood' — rather than merely guessing; it sits a step firmer than 多分 and can carry the flavor of 'I suspect'.
  首相しゅしょうはおそらく辞任じにんするであろう。↗

  The premier is likely to resign.
• まずJLPT N4approx.Common
  adverbBetter known as 'first of all', this adverb's 'probably' sense really means 'almost certainly' — near-certainty rather than a hedged guess — so it is seldom the plain 'probably' you want.
  あのチームは、あるとしても、まず優勝ゆうしょうの望のぞみはない。↗

  That team has little, if any, chance of winning.
• たいていJLPT N4approx.Common
  na-adjective, adverb, nounThis word really means 'usually; mostly'; its 'probably' sense is marginal, suggesting 'in most cases' rather than a speaker's guess, so it is seldom the natural choice for plain 'probably'.

Choose 多分 for plain, everyday uncertainty, 「おそらく」 for a firmer 'most likely' conjecture, 「まず」 only for near-certainty ('almost certainly'), and leave 「たいてい」 aside, since its real meaning is 'usually'.

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

• 多分たぶんprobably
• おそらくprobably
• おそらくはprobably
• ずらprobably
• であろうwill
• だろうにbut I suppose
• まずprobably
• たいていprobably
• ましょうprobably
• まずはprobably
• けだしpossibly
• 大概たいがいprobably
• 大方おおかたprobably