The exact number of feet in a 40-yard dash is 120. There are 3 feet in a yard, so multiplying 40 yards by 3 will give you the number of feet.
American football players often do the 40-yard dash as a speed test. It involves running as fast as you can for 40 yards. Even though some positions are expected to do better on the test than others, the test is usually given to all positions. The faster the time, the higher the score, and the more scouts and coaches will notice a player. The test is meant to be like the distance between the line of scrimmage and a typical punt, where it’s important to get to the ball quickly.