Does Google Penalize For W3C Coding Errors

Generally Google don't penalize for W3C coding errors, Google pages themselves show errors. The only time it would be an issue is when codes affect page rendering

» SEO Archives » W3C Coding Errors

W3C Markup Validation Service Errors

W3C Markup Validation Service Errors

Generally, Google doesn't penalize for W3C coding errors, they themselves have errors on pages. The only time it would be an issue is if the codes affect page rendering or are JavaScript related, or for that matter, not understood by the crawler. Certain coding errors could also raise a red flag with regards to malware or hacking.

Google take malware and hacking quite seriously and in general know which codes to look for, but it is advised to keep your pages clean of code errors and to use the W3C validation Service at

Always remembering that different browsers interpret code errors differently, some browsers more supportive than others. Depending on the code errors and how excessive they are may result in the browser not rendering the page correctly, resulting in a bad user experience.

Matt Cutts had the following to say with regards to invalid HTML and coding error penalties:

So Google does not penalize you if you have invalid HTML because there would be a huge number of webpages like that and some people know the rules and then decided to make things a little bit faster or to tweak things here there and so their pages don’t validate and there are enough pages they don’t validate that we said OK this would actually hurt search quality if we said only the pages that validate are allowed to rank or rank those a little bit higher.

Now I wouldn’t be surprised if they correlate relatively well, you know maybe it’s a signal we’ll consider in the future, but at least for right now do it because it’s good for maintenance, it’s easier for you if you want to change the site in the future, don’t just do it because you think it’ll give you higher search rankings.


Author - Terry

Terry is the owner of Cyber SEO Srvices and specializes in Optimization, Web Design and Digital Marketing and has been worked in the field for over 10 years and in Jan 2019 he qualified as a Google Ads Specialist and Consultant for Google Search, Display, Mobile, Shopping and Video Ads.