WWW vs Non-WWW: Pick One Version and Redirect the Other

Short answer: www.example.com and example.com are technically different addresses. If both load your site, search engines can treat them as two separate sites with the same content. Choose one as your main version and send the other to it with a permanent (301) redirect.

Step 1: check what happens today

Run these from any computer with curl (built into Windows 10 and later, macOS and Linux):

curl -sI http://example.com
curl -sI http://www.example.com
curl -sI https://example.com
curl -sI https://www.example.com

For each, read the first line and the location: header. The ideal result is that three of the four answer 301 with a location: pointing to your chosen version, and only one answers 200. If two or more answer 200, you have a duplicate version problem. If you see a long chain of redirects, see Too Many Redirects.

Step 2: choose your main version

Either works. Pick based on practical points:

Choice	Good for	Watch out for
example.com (non-www)	Shorter, cleaner links	Some DNS providers cannot put a CNAME on the root domain
www.example.com	Easier to move behind a CDN or load balancer with a CNAME	Slightly longer

If your site is already established, keep the version that most of your links and search results use. Changing it later means more redirects to manage.

Step 3: make sure both names point at your site

Both names need DNS records, otherwise the one you redirect away from will not even connect. Typically that is an A record for the root and either an A or CNAME record for www. Check with dig A example.com +short and dig A www.example.com +short. Both should return the address of your host. If a freshly registered domain is not connecting at all, see New Domain Not Working.

Step 4: add the 301 redirect

On Apache, add this to .htaccess to send non-www to www (swap the names for the opposite direction):

RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
RewriteRule ^(.*)$ https://www.example.com/$1 [R=301,L]

On Nginx:

server {
    listen 80;
    listen 443 ssl;
    server_name example.com;
    return 301 https://www.example.com$request_uri;
}

WordPress sites also have a setting for this: the Site Address in Settings, General. Make sure it matches your chosen version. Many hosts and CDNs also offer a one-click redirect rule, which is simpler and safer than editing files by hand. Back up the file before changing it.

Step 5: make everything agree

A redirect alone is not enough. Update:

• canonical tags so they name the chosen version
• your XML sitemap, so it lists only the chosen version
• internal links and any hard-coded URLs
• the property you verify in Google Search Console

Then rerun the four curl commands from Step 1 to confirm.

Common mistakes

• Redirecting with a 302 instead of a 301.
• Redirecting only the homepage and not every path (the redirect should keep the page path, as $request_uri does above).
• Forgetting the HTTPS certificate for the version being redirected.
• Leaving old links, sitemap entries or canonical tags pointing at the other version.
• Creating a loop because the host and the CMS each redirect in opposite directions.