Is a 40 caliber more powerful then 45 caliber handgun?

Answer 1

no, a 45 caliber is way more powerful than a 40 caliber

Actually, it depends. The following is copied from another answer of mine:

The muzzle energy from a .45 caliber round can vary between 350 to a little over 500 ft-lbs, with velocites from about 850 feet per second to over 1000 FPS. The .40 caliber round can range from about 480 to about 570 ft-lbs of energy with velocities ranging from about 1000 FPS to about 1400 FPS. So, in short, it depends on the specifications of the particular cartridges you are comparing.

Answer 2

Thanks