Below you can see the front view size comparison of Nikon P900 and Nikon B700. Nikon B700 is clearly the smaller of the two cameras. Its body is 15mm narrower, 18mm shorter and 30mm thinner than Nikon P900.
Nikon P900 vs Nikon B700 - Front View
Nikon P900 vs Nikon B700 - 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