How to say "ago" in Japanese

• 以前いぜんJLPT N3approx.Common
  noun (suffix)Covers 'ago' as 'before (then)': something that happened earlier than a reference time rather than a counted span — for 'three years ago', use 前. Typical context: saying you have met someone before.
  最善さいぜんを尽つくしますが、よくいっても木曜もくよう以前いぜんに終おえる事ことは出来できません。↗

  I'll do my best, but I'll not be able to finish it before Thursday at best.
• 前まえJLPT N5approx.Common
  no-adjective, adverbCovers the plain 'ago' of English — 'three days ago', 'a few years ago' — as well as 'before', 'earlier' and 'previously'. Typical context: saying how long ago something happened.
  部屋へやに入はいる前まえに靴くつを脱ぬぎなさい。↗

  Take your shoes off before you come into the room.

Use 前 for the plain 'length of time ago' sense ('three years ago') and for 'earlier, before'; use 以前 for 'before (then)' — prior to some reference point rather than a measured span.

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

• 以前いぜんbefore
• 今を去るいまをさるago
• 今を去ることいまをさることdating back from now
• 前まえbefore