Below you can see the front view size comparison of Nikon Z7 and Pentax K-1. Nikon Z7 is clearly the smaller of the two cameras. Its body is 3mm narrower, 9mm shorter and 18mm thinner than Pentax K-1.
Nikon Z7 vs Pentax K-1 - Front View
Nikon Z7 vs Pentax K-1 - Top View
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.
Camera Size Comparison
Select Two Cameras for Size Comparison