一人ひとり or 単独たんどく: Which is Better in Daily Conversations?

2019年8月29日2026年4月21日

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Trying to say “alone” in Japanese? You will quickly run into two options: 一人（ひとり） and 単独（たんどく）. Both can mean “alone” or “by oneself,” yet they are used in very different situations. Getting them confused can make you sound overly formal, robotic, or simply unnatural. This guide clarifies exactly when to use each word.

Yuka

Rei, can I use 単独 to say “I went shopping alone”?

Rei

That would sound very odd! 単独 is used in formal, technical, or serious contexts — like solo climbing or acting alone on a mission. For everyday “alone” activities like shopping, eating, or walking, always use 一人.

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At a Glance

Word	Reading	Register	Core Meaning	Typical Context
一人	hitori	Casual / Neutral	Alone; one person; by oneself	Daily life, personal activities, counting people
単独	tandoku	Formal / Technical	Solo; independently; acting alone	Expeditions, official operations, formal tasks

Hitori (一人) — Alone in Daily Life

一人 literally means “one person” and naturally extends to mean “alone” or “by oneself.” It is the go-to word for everyday situations: eating alone, traveling alone, living alone, doing something without help. It is also used as a simple counter for one person. The tone is warm, natural, and completely appropriate in any daily context.

Example 1:
Japanese: 今日は一人でランチを食べた。
Romaji: Kyou wa hitori de ranchi wo tabeta.
English: I ate lunch alone today.

Example 2:
Japanese: 一人暮らしを始めた。
Romaji: Hitori gurashi wo hajimeta.
English: I started living alone.

Example 3:
Japanese: 一人で解決しようとしないで。
Romaji: Hitori de kaiketsu shiyou to shinaide.
English: Don’t try to solve it by yourself.

Yuka

Is 一人で always followed by a verb to mean “alone doing something”?

Rei

Yes, the pattern 一人で + verb means “to [do something] alone.” But 一人 can also stand alone as in 一人でいい (just one person is fine) or used in compound words like 一人暮らし (living alone).

Tandoku (単独) — Alone in a Formal or Serious Sense

単独 is a formal compound noun. It emphasizes independence and self-sufficiency — often in contexts involving risk, official decisions, or significant undertakings done without the support of a group or organization. You will see it in news reports, business, sports, or any situation where “acting alone” carries weight.

Example 1:
Japanese: 彼は単独でエベレストに登頂した。
Romaji: Kare wa tandoku de Everest ni touchou shita.
English: He summited Everest solo (by himself).

Example 2:
Japanese: その決定は単独で行うべきではない。
Romaji: Sono kettei wa tandoku de okonau beki de wa nai.
English: That decision should not be made unilaterally (on one’s own).

Example 3:
Japanese: 単独犯による事件が増えている。
Romaji: Tandoku han ni yoru jiken ga fuete iru.
English: Incidents by lone offenders are increasing.

Yuka

So 単独 has a more serious or official feeling?

Rei

Exactly. 単独 implies independence and often importance or seriousness. If you used it to say “I went to the convenience store alone,” people would find it very strange — like you were writing a news report about a trivial event!

Common Mistakes

Mistake	Why it sounds off	Correct form
単独でコンビニに行った	単独 is far too formal for a trivial daily errand	一人でコンビニに行った
一人犯による犯罪	一人犯 is not a standard word; this concept uses 単独犯	単独犯による犯罪
Using 単独 to express loneliness	単独 means “solo/independent,” not “lonely.” Loneliness is 孤独 (kodoku)	孤独を感じる (feel lonely)

Side-by-Side Comparison

Situation	Best word
Eating lunch by yourself	一人で
A solo mountain climb reported in the news	単独で
Living alone in an apartment	一人暮らし
A company making a decision without partners	単独で決定する
Expressing that you want to do something yourself	一人でやりたい

Related Words: Kodoku and Hitoribocchi

Be careful not to confuse these “alone” words with words that express loneliness. 孤独（こどく） means “loneliness” or “isolation” — the feeling of being alone. 一人ぼっち（ひとりぼっち） means “all alone” with a sad, isolated nuance. These are very different from the neutral 一人 or the formal 単独.

Decision Flowchart

Are you describing a daily or personal activity done alone?
  YES --> Use 一人で (hitori de)
    Example: 一人で映画を見た / 一人で旅行する

Is the activity formal, official, technical, or serious in tone?
  YES --> Use 単独で (tandoku de)
    Example: 単独飛行 / 単独で交渉する

Are you expressing loneliness or isolation?
  --> Use 孤独 (kodoku) or 一人ぼっち (hitori bocchi)
    Example: 孤独を感じる

Are you counting one person?
  --> Use 一人 (hitori)
    Example: 一人で予約 (reservation for one)