In computing, preview is a function to display a document, page, film, etc. before it is produced in its final form. In the case of printed material this is known as "print preview".

Many interactive websites and online forums allow users to preview their content before submitting it. This is particularly useful on sites with complex markup (not WYSIWYG), where it serves as an opportunity to identify and correct errors and formatting problems before saving the content.

A preview is also known (for a film) as a trailer.