How to say "accumulate" in Japanese

• 溜めるためるJLPT N2approx.Common
  ichidan verb, transitive verbCovers amassing or storing something up, often deliberately: saving money, water, or stamina for later use. The transitive, purposeful sense of accumulating is the core nuance.
  コレステロールをためたくなかったら、脂肪しぼうのない赤身あかみの肉にくを食たべるのがよい。↗

  If you want to avoid cholesterol, eat lean meat with no fat.
• 積み立てるつみたてるCommon
  ichidan verb, transitive verbSpecifically about accumulating savings by putting money aside in installments, such as a pension or college fund. For money saved up gradually, this is the word you want.
• 蓄積ちくせきJLPT N1approx.Common
  noun, suru verb, transitive verb, intransitive verbA noun (also usable as a verb with する) for accumulation of knowledge, data, experience, or fatigue building up over time. Typical in written and analytical contexts.
• 積み重ねるつみかさねるCommon
  ichidan verb, transitive verbTo pile things up layer by layer, most often figuratively for effort, experience, or achievements accumulating through repeated work. Emphasizes the gradual, deliberate stacking process.
  そのバッグは彼かれの後あとに積み重つみかさねられていた。↗

  The bags were piled up behind him.
• 積もるつもるJLPT N3approx.Common
  godan verb, intransitive verbIntransitive: things pile up by themselves, like snow or dust, or worries and work accumulating. It is really for spontaneous build-up, not deliberate amassing, so it seldom works for that sense.
  塵ごみも積つもれば山やまとなる。↗

  Many a little makes a mickle.

Choose 「溜める」 for deliberately storing things up, 「積み立てる」 for saving money in installments, 蓄積 for knowledge or data building up, 「積み重ねる」 for layering efforts, and 「積もる」 for things piling up on their own.

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

• 溜めるためるto amass
• 積み立てるつみたてるto accumulate
• 蓄積ちくせきaccumulation
• 積み重ねるつみかさねるto pile up
• 積もるつもるto pile up
• 積み重なるつみかさなるto pile up
• たまるto collect
• 書き溜めるかきためるto accumulate (writings, compositions, etc. that one has not yet published)
• アキュミュレイトaccumulate
• 描き溜めるかきためるto accumulate (drawings, paintings, etc. that one has not yet published)
• かさむto mount up
• 重ねるかさねるto repeat many times over
• 積むつむto acquire
• 蓄えるたくわえるto accumulate (e.g. knowledge)
• 重なるかさなるto come one after another