How to measure tennis serve speed from video

Decide which speed you want to know

Speed at a particular moment and average speed over a journey answer different questions. A radar reading taken near racket contact describes the early part of the flight. Dividing travel distance by elapsed time describes an average across the chosen interval. Those figures should not be treated as interchangeable.

servespeed provides a video-based speed estimate and technique feedback. It does not replace a radar measurement. No validated accuracy percentage or guaranteed error margin is claimed. A result range is an estimate, not a statistically validated confidence interval; some clips may not support a speed estimate at all.

Set up your phone before serving

Use a tripod or stable support outside the playing area and film in landscape. A rear view, behind the baseline and slightly to one side, can include the player and opposite service box. Check the actual framing before recording a full set of serves.

1. Include the full player, toss, racket contact and ball flight. Keep the bounce visible if possible.
2. Leave court lines in the frame to provide spatial context. Avoid a tight crop around the player.
3. Choose good lighting and check that the ball remains distinguishable against the background.
4. Keep the phone fixed during the serve. Avoid panning, zooming or following the ball by hand.

Keep the recording at its original speed

Prepare one complete serve in a clip no longer than five seconds. servespeed accepts MP4, MOV and WebM files up to 50 MB. Trim away waiting time without cutting out the toss, contact or flight.

Use normal playback at the original recording speed. Avoid slow-motion exports, speed changes, filters and repeated compression. For any separate frame-counting calculation, the recording timeline must be understood: a file saved for slow playback may not describe real elapsed time through its playback frame rate alone. Keep the original file rather than a screen recording or edited social-media copy.

Understand a distance-over-time calculation

A general physics method calculates average speed as distance travelled divided by elapsed time. OpenStax explains this distinction between average and instantaneous speed. This is background information for interpreting measurements, not a description of the servespeed analysis implementation.

For a hypothetical ball travelling 10 metres in 0.25 seconds, the average is 40 metres per second, or 144 km/h. That example does not establish the speed at racket contact. Both the distance and the interval must refer to the same portion of the flight.

The ITF Rules of Tennis define a full court as 23.77 metres long. That length is not the distance of a serve from contact to its first bounce. Contact position, height, direction and landing position change the relevant path. Court markings provide reference points; substituting the full court length into a speed formula would give a misleading result.

Check what the video actually shows

Watch the clip before submitting it. Can you identify contact? Does the ball disappear behind the player, leave the frame or become a blur? Is the camera moving? An unclear start or end point makes timing uncertain, while perspective makes screen distance difficult to interpret as physical distance.

If key evidence is missing, record another serve with clearer framing. A larger or sharper file cannot recover an event that happened outside the frame. Treat an unavailable speed as a reason to improve the recording, not as a zero-speed result.

Submit your clip to servespeed

Choose your video and review it, then sign in with Google to submit an analysis. Selecting a file alone does not upload it. Upload begins when you agree to the notice and start analysis.

Both your account and this browser must have their one free analysis available to use the free allowance. Further analyses require 10 credits each. Check the pricing page before buying credits.

Submitted videos enter an asynchronous queue. Results are not immediate, and there is no guaranteed completion time. Check the task status and return to view the estimate and feedback when available. A completed analysis does not guarantee that the video supports a ball-speed figure.

Use the result to review your practice

Keep the original clip alongside the result and read the technique feedback as well as the estimated range. For later recordings, keep your camera position and framing consistent. Small differences between estimates do not by themselves demonstrate a change in your true serve speed.

When comparing with another tool or a radar device, first check which part of the flight each result describes. For a verified measurement, use an appropriate calibrated measurement setup; this video estimate does not certify a personal record.