# Does URL encoding create duplicate content?

An SEO expert was testing my site, and noticed that my URLs contained the special character :. He said that would create duplicate content, because google would interpret any url containing : as two separate URLs: one with : and one with %3A. Is he right?

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I'm tempted to edit this and put "so called" before "SEO export" (and keep the quotes around "so called"). –  paulmorriss Jun 28 '12 at 13:28
Also, next time you ask a question, can you not begin the title with SEO? Thanks –  Christofian Jun 28 '12 at 17:20
I think that he ran a software or website on your site and it told him that. Different search engines behave differently. Regardless, it might be a best practice to avoid : in URL's. –  B Seven Jul 4 '12 at 19:03

## 1 Answer

I suspect this is lies/misinterpretation from your "SEO expert" (such roles do not exist IMO). Essentially %3A and : are exactly the same thing, one is just encoded and means exactly the same thing, anything that reads an URL will know that.

Otherwise you could argue that any non-alphanumeric character could cause duplicate content as they all have an URL encoded entity for someing (eg %2d is -).

IE:

http://webmasters.stackexchange.com/questions/31499/seo-whould-i-use-in-url


and

http://webmasters.stackexchange.com/questions/31499/seo%2dwhould%2di%2duse%2din%2durl


Both resolve to the same place, except that - is url encoded in the latter and is what will be honoured by browsers/search engines.

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well I know that and I told him that this is just the encoding. But he told me that search engines see those as different things –  gong Jun 28 '12 at 13:19
Well he's an idiot. SEO experts is such a non-existent profession in my opinion, if were so good at SEO and good become #1 in SERPs for any website you would make much more money doing that then teaching others! –  Dunhamzzz Jun 28 '12 at 13:37
"any non-alphanumeric character could cause duplicate content" <- or any character at all, since alphanumeric characters can also be encoded. –  DisgruntledGoat Jun 29 '12 at 13:27
@DisgruntledGoat src? How would that even work? Isn't the idea of url encoding is to convert the potentially out-of-chracterset symbols to alhapnumeric? –  Dunhamzzz Jun 29 '12 at 14:33
@Dunhamzzz more or less, yeah. But every character has an encoding, it's just not needed with basic letters/numbers. Actually some browsers (e.g. Chrome) will convert all encoded URLs and display the actual characters, even for foreign alphabets. –  DisgruntledGoat Jun 29 '12 at 19:13