Macworld Tim Cook giveth, and Tim Cook taketh away. We’ve long known that while this fall’s iPhone 17 Air is set to be an astonishingly slender and lightweight device, it will come with a painfully small-capacity battery to compensate. And now we have a better idea of exactly how painfully small it will be. A leaker and blogger going by the name yeux1122 claims to have uncovered the weight, thickness, and battery capacity of the 17 Air based on what they describe (via Google Translate) as a “mass production confirmed sample.” The first is 5.5mm, which sits at the low end of what we’ve already heard from other sources: previous reports have said “around 6mm,” 6.25mm, and 5.5mm, so this is about as slim as we could have hoped. And the weight is a startlingly low 145g, which would significantly undercut even Samsung’s 163g Galaxy S25 Edge. Wow, frankly. Wow. But the sting in the tale is the battery, which yeux1122 claims has a capacity of just 2,800mAh. If accurate, that would be substantially lower than any model in the 14-, 15-, or 16-series iPhone generations; the lowest last year was the 6.1-inch iPhone 16 at 3,561mAh, so we’re looking at 21% less battery to power a considerably larger (6.65 inches, if the rumors are correct) display. The only iPhones with less than 3,000mAh in recent history were the iPhone 13 mini (2,438mAh) and 3rd-gen SE (2,018mAh), but those batteries had to power screens measuring just 5.4 and 4.7 inches, respectively. You can see battery capacities and screen sizes for all the iPhones since 2021 at the bottom of this article if you want to compare. User experience is more than just numbers on a spec sheet, of course, and it remains to be seen how the 17 Air will hold up in real-world performance. However, earlier reports claimed Apple will be selling a battery case to compensate for the phone’s low battery life, which kind of defeats the purpose of an ultra-thin phone. Rest assured that Macworld will run exhaustive battery tests as soon as we get our hands on one—but it might be worth calibrating your expectations at the lower end. iPhone 17 Air (6.65 inches): 2,800mAh iPhone 16e (6.1 inches): 4,005mAH iPhone 16 (6.1 inches): 3,561mAh iPhone 16 Plus (6.7 inches): 4,674mAh iPhone 16 Pro (6.3 inches): 3,582mAh iPhone 16 Pro Max (6.9 inches): 4,685mAh iPhone 15 (6.1 inches): 3,349mAh iPhone 15 Plus (6.7 inches): 4,383mAh iPhone 15 Pro (6.1 inches): 3,274mAh iPhone 15 Pro Max (6.7 inches): 4,441mAh iPhone 14 (6.1 inches): 3,279mAh iPhone 14 Plus (6.7 inches): 4,323mAh iPhone 14 Pro (6.1 inches): 3,200mAh iPhone 14 Pro Max (6.7 inches): 4,323mAh iPhone SE (3rd gen) (4.7 inches): 2,018mAh iPhone 13 (6.1 inches): 3,240mAh iPhone 13 mini (5.4 inches): 2,438mAh iPhone 13 Pro (6.1 inches): 3,095mAh iPhone 13 Pro Max (6.7 inches): 4,352mAh iPhone 17 Air specs unconfirmed and sourced from yeux1122; other specs sourced from GSMArena.