I'll keep you posted vs Inform

When to use each in English, with meaning, register, and examples.

I'll keep you posted

InformalTop 2,000 (common)

Inform

Top 2,000 (common)B2verb
Most formal: Inform
 I'll keep you postedInform
Pronunciation🇬🇧 //aɪl kiːp jʊ ˈpəʊstɪd//🇺🇸 //aɪl kip jʊ ˈpoʊstɪd//🇬🇧 /["/ɪnˈfɔːm/","/ɪnˈfɔːmz/","/ɪnˈfɔːmd/","/ɪnˈfɔːmɪŋ/"]/🇺🇸 /["/ɪnˈfɔːrm/","/ɪnˈfɔːrmz/","/ɪnˈfɔːrmd/","/ɪnˈfɔːrmɪŋ/"]/
MeaningI'll let you know the latest news.To tell someone something important or give them information.
ExampleI'll keep you posted on the project's progress.Please inform me of any updates regarding the project timeline.
RegisterInformalNeutral
How commonTop 2,000 (common)Top 2,000 (common)
CEFR level-B2
Part of speechverb
Collocationskeep someone posted, keep you updated, keep me informedmerely, simply, regularly, be pleased to, regret to, be required to, about, of
Antonyms-conceal, withhold, hide
Common mistakesUsing it in formal emails where more formal language is required., Confusing it with 'keep in touch', which implies broader communication.Confused with 'informant' — 'inform' is a verb, not a noun., Using 'inform' without an object — always say who you are informing., Misusing tenses — ensure correct form like 'informed' for the past.
Usage notesCommonly used in casual conversations to indicate you will update someone on progress or news. Less appropriate in formal situations.Use 'inform' in formal contexts, like writing or business. Avoid in casual conversations where 'tell' is more appropriate.

See it in real clips

I'll keep you posted
Inform

Frequently asked questions: I'll keep you posted vs Inform

What's the difference between I'll keep you posted and Inform?

I'll keep you posted: I'll let you know the latest news. Inform: To tell someone something important or give them information.

Which is more formal: I'll keep you posted and Inform?

Inform is the most formal of these.

Can you show an example of each?

I'll keep you posted: I'll keep you posted on the project's progress. Inform: Please inform me of any updates regarding the project timeline.

Can I use I'll keep you posted and Inform interchangeably?

Not always. I'll keep you posted and Inform are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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