Is a 4.65-inch screen just too big to use with one hand? We got a dozen PCMag staffers to try the Samsung Galaxy Nexus to find out.

The is the biggest phone in America. At 5.33 by 2.67 by 0.37 inches, with a whopping 4.65-inch screen, it's dangerously close to a tablet.

But it's just the latest in a line of almost comically huge, or at least huge-screened phones coming to market. The has a 4.3-inch screen, but it's about the same size as the Nexus. The has a 4.5-inch screen and measures 5.11 by 2.71 by .37 inches—shorter, but wider. The HTC Titan packs a 4.7-inch screen into about the same body size.

Are these phones too big for the human thumb? Most phones should be usable one-handed—at the very least, you should be able to swip down the notifications bar and check your messages. I got a dozen PCMag staffers to measure their thumbs, hold the Galaxy Nexus in one hand, and try to check text messages by dragging down the phone's notifications bar.

Of course, it matters how you hold your phone. There are two main grips: with the bottom corner of the phone against the pad below your thumb, and a sort of crosswise grip with your hand across the middle of the phone. But ideally, you should be able to span the screen one-handed no matter how you're holding the device.

The six female staffers we measured generally had thumbs 5-6 cm long. There was a wider range with the men; they had thumbs 6-9 cm long.

None of the ladies could span the Galaxy Nexus's screen with their thumbs. For them, operating the phone meant shifting it around in their hands; a few gave up entirely on trying to pull the notification bar down.

The men had better luck. The threshhold for comfortable use seemed to be having a 7-centimeter thumb, which four of our six men had. My thumb measures in at about 6.4 centimeters, and I definitely had some trouble using both the Galaxy Nexus and the Motorola Droid Razr one-handed.

What does this mean for phone design? Apple fans have crowed for years that 3.5-inch screens are the perfect size, but I don't think you have to go that small to find a screen that's usable by a wide range of people. In this office, 4-inch screens like the one on Verizon's seem to be a happy medium for everyone, and even a well-designed 4.3-inch phone can seem like it isn't too overwhelming.

When is a phone too big? Is the Galaxy Nexus too big for you? Tell us in the comments thread below, and check out our slideshow to see how PCMag thumbs reacted to the huge Galaxy Nexus screen.

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