You'll find a wide range of standard measurements on Windows24.com and you can also choose a custom size. Naturally, the ideal size of your back door depends on how much space is available, who will use the back entrance and so on. As a general suggestion, you may not want to make your back door narrower than the front door since the back entrance is typically what you'll use to get the shopping home. Or maybe you'll want to store your bike inside during the cold winter months. Use our online configurator to customise the width and height of your back entrance door.