Tennis Serve Speed: How to Measure It and Averages by Level

A tennis serve is fastest the instant it leaves the racquet, then slows quickly from air resistance and the bounce as it crosses the court. That's why, when measuring serve speed, which stretch you measure matters a lot.

Serve speed by level (approximate)

The speeds shown on pro tournament broadcasts are radar readings taken "right off the racquet." If you measure the average over the whole serve from video, it's normal to get a lower number.

How to measure it with your phone

1. Film from the side: Set up near the net post and fix the phone so everything from the baseline to the service line is in frame.
2. Choose the stretch: The usual approach is to measure from racquet contact to just before the ball bounces in the service box.
3. Enter the distance: From the baseline to the service line on the other side of the net is about 18.29m (a bit longer on a diagonal). The contact point is in front of the baseline and the bounce lands short of the service line, so the actual flight distance varies every time. It's roughly 17–20m; measuring against marks on the court works best.
4. Shoot in high speed: Serves are very fast, so 120fps or higher is recommended.

Tennis balls are easy to spot by color

Optic-yellow tennis balls stand out sharply from the background, so automatic detection tends to work well. On the other hand, if the court color is similar or you're shooting into the sun, the ball is hard to see, so film with the sun at your back.

Practice points for a faster serve

• Use your legs and trunk rotation before arm strength.
• Toss to the same spot every time.
• Don't squeeze the racquet; keep your wrist loose.

Logging your speed consistently lets you check right away whether a change in form actually made you faster.