User blog comment:OVERPOWERED99/2 questions to ask/@comment-24990845-20150204133505/@comment-25145866-20150204140055

Nightmares are one of the bigger dragons out there, they're definitely large-sized. Somewhere more than 10 meters looks large to me but for dragons, somewhere around 5-14 meters are medium. If you've seen a person that is around 2 meters tall, you can see they look big compared to you, at least for me although I'm quite tall for my age. Times that by 5 and you'll get how large dragons can be.