Url outside the loop

Just copy and paste below code. you can replace ‘get_the_ID()’ with page/post id otherwise it will return image for current page/post. cheers!!!

$size = "full";
$urlarr = wp_get_attachment_image_src(get_post_thumbnail_id(get_the_ID()),   $size);

$imgurl = $urlarr[0];

this will return complete url of the image.