After rumors of an Apple iPhone Air circulated immediately after the M4 iPad Pro’s major diet, the topic of thinner phones seems to be back on the table. But just like OLED TVs with thin tops and thick backsides, a phone is only as thin as the thickest part of its body: the camera bump.

Phones are getting thinner

There’s definitely a trend toward thinner phones, and considering what a lethal hulk my first phone was (a Nokia 2110), that’s generally a good thing. But how thin does a phone need to be? The Galaxy S24 Ultra and iPhone 15 Pro are both about 0.33 inches thick, so 8.6 and 8.4 millimeters respectively. My own S22 Ultra is just under 9mm thick, and I can’t imagine there’s any point in shrinking that any further, but maybe we’ll see an iPhone 17 Air that’s just 5mm, or 0.19685 inches, thin at some point.

Now, I’m not the biggest fan of thinness per se, but these numbers clearly attract customers. It’s also a bit of a cheat, because the thickness of the phone doesn’t include the camera bump!

Camera bumps, er, increase the thickness

The last phone I had that didn’t have a camera bump was my Note 10 Plus, which had the cameras practically flush with the body of the phone. My S21 Ultra had a chunky old bump, and my current S22 Ultra has reduced that significantly, though it’s far from gone. My iPhone 13 Pro and 14 Pro both had shameless camera blocks. The iPhone 14 Pro adds another 4.18mm to the phone’s 7.85mm body, so is it really a half-inch phone or a third?

Big bumps, big wobbles

I used to be an advocate of naked phones and would still prefer that, but the camera bulges on my modern phones have basically made me buy leather cases for them. Because of these bulges, the phones don’t grip well in the hand and are wobbly on flat surfaces, which, believe it or not, I often use them on. The case essentially flattens the back and makes the camera bulge flush.

Cases reveal the true thickness

Since the case makes the phone thicker to accommodate the camera bulge, this is the actual thickness of the phone. The practice of specifying the thinnest part of a device, as was the case with the MacBook Air’s wedge-shaped design or OLED TVs with large bottoms, is a marketing tactic. It would be one thing if the majority of people didn’t use phone cases, or if phones with large bulges felt fine to use without a case, but in my opinion these are the exception rather than the rule. That means you should add the size of the camera bulge to the phone’s stated numbers to get the real story, a number that manufacturers themselves generally don’t provide.

Don’t fall for the hype

If it turns out that Apple is actually releasing a phone with a 5mm body, and a number of other manufacturers will inevitably follow suit, like so many lemmings falling off a cliff, then it’s worth a moment’s reflection. A collective sanity check. Especially if it’s actually a 10mm phone thanks to its camera.

Thinner devices look great, are impressive, and feel like a step forward. However, if you’re going to make something smaller or thinner, it has to serve some purpose of value. I have to get some significant benefit out of it. If they’d just made the phone as thick as needed to keep the camera bump flush, maybe it could have had better cooling and performance. Maybe a few more hours of battery life. Better speakers, more ports, or (shock) a headphone jack.