At first glance, you'd think that – aside from the smaller notch – the iPhone 13 and 13 Pro are identical in size to the iPhone 12 and iPhone 13 Pro.
But this is not the case; looking at the spec sheets (via Ars Technica) you'll find some subtle (and not so subtle) differences.
For example, the iPhone 13 Pro is quite a bit heavier than the iPhone 12 Pro — 204 vs. 189 grams. It's also a hair thicker: 0.3 inches vs. 0.29 inches, with the rest of the dimensions equal.
There's a smaller but still notable difference in weight between the iPhone 13 and the iPhone 12; 174 vs. 164g. The iPhone 13 Pro Max weighs 240g, while the iPhone 12 Pro Max weighs 228g. Finally, even the tiny iPhone 13 mini is heavier than the iPhone 12 mini: 141 vs. 135 grams. All of the iPhone 13 devices are equally thicker than their iPhone 12 counterparts: 0.3 vs 0.29 inches.
The extra thickness and weight could have something to do with the increased battery life in the new iPhones, which is considerably better than last year's devices. Also, Apple said that it thoroughly redesigned the iPhone 13's insides to make room for the upgraded battery.
For most users, the differences in weight and thickness probably won't be dealbreakers, but they are notable. It's also possible that cases for the iPhone 12 phones won't fit their iPhone 13 counterparts, which might mean additional costs if you're switching from one to the other.