The new iPhone 6 and 6 Plus were made available yesterday. Both are a bit bigger than previous versions of the phone, and that means using them is a little different. Over on Quartz, designer Scott Hurff shows how reachable the new phones are.
Obviously, everyone's hands are different, but Hurff created a map of the "Thumb Zone" using research from Steve Hooper. The result is that you'll have to stretch out your thumb quite a bit to hit everything on the iPhone 6, and the iPhone 6 Plus is basically impossible to use one-handed. Apple solves this problem with Reachability, a new one-handed mode for the new models, but it's still good to know what you're getting into. The same goes for any larger phone. Hurff has a lot of data and insights over on Quartz if you want to see more.