While gauging the exact "power" of your strike would be extremely difficult, but utilizing pounds per square inch is a simple way to get a ballpark estimate, and improve your form to maximize your number of pounds per square inch.
If you're into math, you're basically taking the number of pounds of force in your strike (let's just say 100 in order to make the math simple), and then you are dividing it by the number of square inches of surface area that is making contact when your strike lands.
So 100 pounds of force divided by 10 square inches of surface area would only allow for a 10 pound strike. While the same amount of force divided by 2 square inches of surface area would yield a 50 pound strike.
This is why in many styles of martial arts the idea of focusing your strike into a smaller amount of surface area is part of the technique. One example of many in Shobayashi-Ryu would be that in our basic "punch" you are often taught to strike with only the first two knuckles rather than the entire flat fist.