W3C Link checker is a free online tool that can be used to find broken links on a website or web page. The tool crawls the website and reports invalid links and warnings.
The tool works well and reports broken links and redirect warnings. If you are trying to check links for website, make sure ‘Check linked documents recursively’ is checked. There is a limit on number of documents the tool will search, so it may not be the right tool for big websites.