How Fast Is Tennis Serve (pro)?

A pro tennis serve hits 70 m/s — over 250 km/h. The ball crosses the court in 0.3 seconds, less than human reaction time. Top returners react to body cues from the server's wind-up, not to the ball itself once it has been struck.

The fastest recorded tennis serve was 263 km/h by Sam Groth in 2012 — though the ATP doesn't recognise it as the official record.

• Same as a small jet airliner
• Crosses the court in 0.3 seconds