How to say "automatically" in Japanese

• ひとりでにJLPT N2approx.Common
  adverbCovers 'automatically' in the sense of something happening by itself, without anyone operating it. The word also means 'naturally' or 'of its own accord', so the nuance is spontaneous, mechanical self-action.
  ろうそくはひとりでに消きえた。↗

  The candle went out of itself.
• 直ちにただちにJLPT N3approx.Common
  adverbOnly covers 'automatically' in the logical sense that one thing automatically means or results in another. It is not about machines acting by themselves; for that use, this is rarely the word you want.

Use 「ひとりでに」 when something happens by itself without outside intervention, and 「直ちに」 when 'automatically' means that one thing directly or immediately results in another.

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

• ひとりでにby itself
• 勝手にかってにarbitrarily
• ところてん式にところてんしきにsystematically
• 自然しぜんnaturally
• 直ちにただちにdirectly (face, lead to, etc.)