The iPhone 11 Pro Max is just slightly bigger than the iPhone XS Max. However, both of these models have the same size display (6.5 inches).
The iPhone 11 Pro Max has a longer lasting battery that tends to charge faster. The iPhone 11 Pro Max has a more advanced 3 lens camera rather than the dual lens on the XS Max. The 11 Pro Max is also slightly thicker and weighs 18 grams more than the iPhone XS Max.
Perhaps the main difference is that the XS Max has the A12 bionic chip and the 11 Pro Max has the A13 bionic chip. Both are high performance but the A13 bionic chip is 20% faster while using 40% less power. Meaning that the A13 is higher performing and more efficient.
- iPhone 11 Pro Max: 6.22 x 3.06 x .32 inches (HxWxD)
- iPhone XS Max: 6.20 x 3.05 x 0.30 inches (HxWxD)