Redirect HTTP to HTTPS

To avoid duplicated content make sure your website is only available under one address (with www. or without / with http or https).

To redirect all http requests to https use the following code in .htaccess:

<IfModule mod_rewrite.c> 
    RewriteEngine On
    RewriteCond %{HTTPS} off
    RewriteRule (.*) https://www.your-domain.com%{REQUEST_URI} [R=301,L]
</IfModule>
# BEGIN WordPress

To redirect all requests without www. to www. and use https put the following code in .htaccess:

<IfModule mod_rewrite.c> 
    RewriteEngine On
    RewriteCond %{HTTP_HOST} ^your-domain.com$ [NC]
    RewriteRule (.*) https://www.your-domain.com%{REQUEST_URI} [R=301,L]
</IfModule>
# BEGIN WordPress

Combining both rules would look like this:

<IfModule mod_rewrite.c> 
    RewriteEngine On
    RewriteCond %{HTTPS} off
    RewriteRule (.*) https://www.your-domain.com%{REQUEST_URI} [R=301,L]
    RewriteCond %{HTTP_HOST} ^your-domain.com$ [NC]
    RewriteRule (.*) https://www.your-domain.com%{REQUEST_URI} [R=301,L]
</IfModule>
# BEGIN WordPress

Replace both your-domain.com with your domain.