How fast the ball is moving the instant it leaves the clubface, in mph. It's the single biggest ingredient in distance — every extra 1 mph of ball speed is worth roughly 2 yards of carry with a driver. PGA Tour players average about 170 mph off the tee; a typical male amateur is closer to 130–140. Ball speed is what clubhead speed becomes after impact, so a slower swing with a pure strike can out-fly a faster swing that catches the heel.