English UsageGrammar guide

So vs. Such

“So” and “such” can both intensify meaning, but their grammar differs. “So” normally modifies an adjective or adverb, while “such” introduces a noun phrase.

Quick answer

Use “so” before adjectives or adverbs (“so useful”); use “such” before noun phrases (“such a useful tool”).

Key details

Core Patternso + adjective/adverb; such + noun phrase
So Roledegree adverb commonly modifying adjectives and adverbs
Such Roledeterminer used before noun phrases

Further guidance

Adjective Boundary

Use so before an adjective or adverb when expressing degree.

Noun Phrase Boundary

Use such before a noun phrase, including patterns such as “such a good idea.”

Sources and evidence

Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.

  1. Such or so? — English Grammar Today (opens in a new tab)Cambridge Dictionary · So before adjective/adverb phrases and such before noun phrases

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