とは限らない【とはかぎらない】

The expression とは限らない means "not necessarily", "it is not always the case that", or "there is no guarantee that". It is used to challenge assumptions, generalizations, or common beliefs by pointing out that something is not always true.

Basic Usage

Attach とは限らない to the plain form of verbs, adjectives, or nouns to express that something is not necessarily the case.

With nouns and な-adjectives

When connecting to nouns or な-adjectives, use だ (or である) before とは限らない. However, だ is often dropped in this pattern.

With negative forms

とは限らない can also follow negative forms to mean "it's not necessarily the case that something does not happen" – in other words, "it doesn't mean it won't / can't".

Nuance

This grammar pattern is used to warn against overgeneralizing, to temper expectations, or to express a more nuanced perspective. It carries a tone of caution or gentle correction. It is commonly seen in both spoken and written Japanese.

A closely related expression is ともかぎらない限らない, which has the same meaning but is slightly more conversational.