Supposed to

How to use "supposed to" correctly

This is an entry on my list of Common Errors in English Usage. Visit the main page for direct links to additional entries.

Supposed to is a descriptive expression derived from the passive voice, so the past participle supposed is always the correct form when it is used to mean “permitted,” “required,” or “expected”:

was suppose to be home by 12
was supposed to be home by 12

not suppose to do that
not supposed to do that

The mistake of leaving off the participial suffix is very common and easy to understand; we rarely pronounce both the ending d and the following to clearly and distinctly, so they naturally blend together into one sound as if the suffix were not present.

Related Resources

Common Errors in English Usage: Errors in diction and idiom commonly made by native speakers of English

List of Common Errors in English Usage (PDF): Printable version of the complete list

Common Grammar Errors: A list of common errors in grammar (topics like subject-verb agreement and parallelism) as distinct from usage

List of Common Errors in English Usage: PDF version

© 2006, 2008, and 2019 C. Brantley Collins, Jr.