URL change extension to .php from .htm

[Zilla]

I am looking at changing the platform of an established (7 years) site to PHP based.

Currently most of the URLs have the file extension .htm (“x.com/filename.htm” ) with some URLs being indexed as directory URLs (“x.com/directory/” feeding from “x.com/directory/index.htm”)

So I am considering two options

• A. Changing just file extensions & create 301 redirects, (x.com/samefilename.htm” -> “x.com/samefilename.php”) and for directory URLs (“x.com/samedirectory/index.htm” -> “x.com/samedirectory/index.php”)

• B. At the same time taking the opportunity to change the file hierarchy to be more user / seo friendly by changing all URLs to directory URLs – this would be a more extensive redirect than just changing the file extension.

I am interested in what risks / impact would there be of this and the questions I would like some help with are:

1. Are there any short term risks to rankings with a filename extension change like this?
2. Should an exercise like this be staggered or is it ok to carry out the site-wide change in one go?
3. Does a more extensive filename and structure redirect like in option B above introduce more risk than just changing to the .php extension or would the search engines consider this the same?
4. For the directory URLs do I even need a 301 redirect after changing index.htm to index.php or will the Search engines not even recognise a change (indexed URL will remain the same)?

Your opinions on the above questions and any other advice / experience you can share would be much appreciated.

Thanks,

Adrian.

[AndyAtkins]

Istvan makes a number of good points and Matt Cutts has certainly alluded to a loss of some link juice when using 301's, although Google's official line is that there is no loss. I'd not seen the 15% number before, which is certainly high enough to be discernible above the 'noise'.

I support his contention that, in terms of getting existing inbound links repointed, it's best to focus on the few high value links and then look for new links driven by quality content. This has the double benefit of cleansing some of the now-devalued link types, whilst appealing to Google's measurable preference for 'fresh' links.

[Keszi]

Hi Adrian,

with a 301 you lose aprox 15% of link juice (don't remember who gave that exact number, but i still have that in my mind )

So basically if you can change the links that you have control of, it will help. with other links... try to focus more on gaining new link partnerships. the 301 will lose some of the link juice, but new partners will push the link diversity and will help you more.

I hope it helped and good luck ;-),

Istvan

[Zilla]

Thanks Istvan and Alan for the responses.

On the subject of incoming links - I can change internal links and inbound links from other sites I control however the vast majority of links will still point to the old page location so my follow up question is just how serious is this link juice loss due to the 301 and is this a serious enough reason to not do the change and keep the locations as they are now?

[Keszi]

Thank you Alan

[AlanMosley]

Istvan is give a good answer, i would add one thing, make sure all your internal links point to the new urls, dont rely on the 301, as as Istvan stated, they will leak a little link juice.

[Keszi]

Hi Adrian,

We had a similar problem not as long ago (changing the website extension from .html to .aspx). What we have experienced is, that the website traffic and rankings went down for aprox. 1-2 week, then it came back up without any problem.

I would suggest to go for all change at one time instead of going with partial rewrite, then again some partial rewrite. (Before you put it alive, test all your links! check for broken links and make sure the redirects are right)

After the website deploy you should resubmit a new sitemap in GWT.

The 301 should be done, so after resubmitting your sitemap in GWT you will not face any duplicate content issue.

The negative part: you will lose some of the link juice thanks to the 301. If you have the possibility contact the webmasters who are already linking to your website and ask them kindly to resolve the URL issue (at least for the highest authority links you have gained in time).

I hope that helped,

Istvan