Having broken links on your website can cause search engines to assume your site is not properly maintained. This may cause search engines to penalize your site.
Instead of going through your entire site and making sure your links are all correct, you can simply download Broken Link Checker.
Once you install this plugin you can go to Tools > Broken Links and in the General tab you can find Status – this will show you how many links are broken. Come back to this after a few minutes so the plugin has time to find all broken links.
Click on the “Found 12 broken links” link and it will show you a list of your broken links.
Check through your links by editing current URL, unlinking the current link, telling the plugin it is not broken, dismissing the error or have the plugin recheck.
This plugin can (optionally) mark broken links as ‘nofollow’ automatically so that search engines don’t get a negative impression about your site. You can also receive an email notification whenever new broken links are detected on your site to help you stay on top of broken links.