Look ma, one hand! The supersized smartphone challenge

See exactly how much of the iPhone's or Galaxy's screen you can actually reach with your thumb

We all know that the trend for smartphones is to get bigger and bigger. Samsung pushed the development several years ago with its Note "phablet" supersized smartphone, and Apple joined the party this fall with the iPhone 6 and iPhone 6 Plus.

But how big is too big? Expert Exchange blogger Leslie Bloom decided to map the reach of the average man's and average woman's thumb to the screens of the Apple iPhone 6, Samsung Galaxy S5, iPhone 6 Plus, and Galaxy Note 4, the current iOS and Android flagship smartphones.
Unsurprisingly, the bigger the phone, the less likely a person can reach its full screen when using it one-handed — even when stretching their thumb beyond its natural radius. Women, whose hands tend to be smaller, are particularly limited in how much of the screen they can reach when using the smartphone with one hand.

Of course, when you buy a big phone, you know it's big. The supersized screens are popular, so people clearly aren't disadvantaged by the more difficult one-handed operation they present. Many people use them as a microtablet, with two hands, for example.

Still, you don't always have two hands free, so the large screen can pose issues. That's why both Apple and Samsung have features for their flagship phones that reduce the screen temporarily for one-handed use. Bloom didn't analyze how those one-handed modes fit the average user's thumb reach, so I did. As you would hope, the one-handed modes make the iPhone and Galaxy screens accessible for one-handed operations.

The graphic below shows the natural reach of an average man and woman's thumb (green), the "stretch" reach (yellow), and the unreachable area (red). I reworked Bloom's images for clarity and made copies onto which I highlighted the portion of the smartphone screens available when in one-handed mode, so you can see the reach in those modes.