Rules, comparisons and data

Should you use idioms in IELTS Speaking?

Only if you can use them naturally. Idiomatic language appears in the Lexical Resource descriptors from band 7 upwards: 'some ability to use less common and idiomatic items' at band 7 and 'skilful use' at band 8. IDP warns that idioms are difficult and do not always sound natural, so use them only when you are sure how. They are one part of vocabulary, not a requirement.
  • Guide updated · 30 October 2026
  • 3 sections
  • IELTS
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Written byFizza Butool ZaidiIELTS teacher for 10+ years, PTE for 5Updated 30 October 2026

Idioms in the Speaking descriptors

From the Lexical Resource column of the Speaking band descriptors.

BandLexical Resource wording
9Sustained use of accurate and idiomatic language
8Skilful use of less common and idiomatic items despite occasional inaccuracies in word choice and collocation
7Some ability to use less common and idiomatic items and an awareness of style and collocation is evident though inappropriacies occur
6Resource sufficient to discuss topics at length. Vocabulary use may be inappropriate but meaning is clear.

What IDP advises

IDP's Speaking FAQ: 'Using idioms in the IELTS Speaking test can be helpful, but be careful because idioms are difficult to use and do not always sound natural. Make sure you are sure how to use them correctly' (IDP).

The Speaking key assessment criteria list collocation 'including idiomatic expressions' alongside style, correct labelling of things and paraphrase. An idiom in the wrong register or context counts against appropriacy.

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Idioms in Writing

The Writing descriptors use similar wording: band 7 Lexical Resource shows 'some ability to use less common and/or idiomatic items' (Writing band descriptors). ielts.org asks for an academic or semi-formal/neutral style in Academic Writing, so very informal idioms rarely suit an essay (ielts.org).

Frequently asked questions

Do I need idioms for band 7?+

Band 7 describes 'some ability' to use less common and idiomatic items. Precise, less common vocabulary also counts; idioms are not mandatory on their own.

Will a memorised idiom list help?+

IDP warns idioms often sound unnatural. The descriptors also mark down memorised language at low bands.

Are phrasal verbs idioms?+

The descriptors do not define them separately. They fall under vocabulary range, collocation and appropriacy.

Can I use slang?+

IDP says slang is not itself evaluated, but Lexical Resource does judge whether your words suit the style of the conversation.

Keep reading

Related

Guide updated on 30 October 2026. Individual prices and policies may have earlier observation dates. Confirm current details on the linked official pages before you book or apply.

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