Apple Watch Ultra 3 vs Apple Watch Ultra 4: Size & Dimensions

The Apple Watch Ultra 3 and Apple Watch Ultra 4 share nearly identical dimensions — the practical difference comes down to weight, materials, or other specs rather than size. They match almost exactly in height, at 49.0 mm. They match almost exactly in width, at 44.0 mm. They match almost exactly in thickness, at 12.0 mm.

The Apple Watch Ultra 4 is the heavier of the two at 63 g, compared with 61.6 g for the Apple Watch Ultra 3. That is a 1.3999999999999986 g difference (2%). The gap is small enough that you would barely notice it day to day.