Tennis Serve Speed Converter
Convert tennis serve speeds instantly between mph and km/h. Use this when scouting players, analyzing match data, or comparing serve speeds across international broadcasts that use different units.
About this calculator
Tennis serve speeds are measured in miles per hour (mph) in the United States and kilometers per hour (km/h) in most other countries. Converting between the two requires multiplying by the fixed ratio between the units. The formula is: speed_kmh = speed_mph × 1.60934. This constant (1.60934) represents the exact number of kilometers in one mile. For the reverse conversion, divide by 1.60934 (or multiply by 0.62137). World-class servers like John Isner regularly clock serves above 230 km/h (143 mph), so accurate conversion matters when comparing player statistics across different data sources or broadcasts.
How to use
Suppose a player's first serve is clocked at 130 mph on a US broadcast, and you want the km/h equivalent for a European stats sheet. Apply the formula: speed_kmh = 130 × 1.60934 = 209.2 km/h. Conversely, if a serve is listed as 200 km/h, divide: 200 ÷ 1.60934 = 124.3 mph. Enter your mph value in the Serve Speed field and the calculator returns the km/h result instantly, removing any manual conversion errors.
Frequently asked questions
How do I convert tennis serve speed from mph to km/h accurately?
Multiply the mph value by 1.60934 to get km/h. This constant is the precise number of kilometers in one statute mile. For example, 140 mph × 1.60934 = 225.3 km/h. Using the exact constant rather than rounding to 1.6 prevents small but cumulative errors when comparing multiple serves.
What is the average professional tennis serve speed in mph and km/h?
The average first-serve speed on the ATP Tour sits around 180–200 km/h (112–124 mph) for men, while WTA players typically average 150–170 km/h (93–106 mph). Second serves are considerably slower, often 130–160 km/h (81–99 mph), to prioritize spin and placement over raw pace. Top servers like Reilly Opelka and Sam Groth have recorded official first-serve speeds exceeding 250 km/h (155 mph).
Why do some tennis broadcasts show serve speed in mph while others use km/h?
The unit used depends primarily on the country of broadcast. US tournaments and networks default to mph, while European and Australian broadcasts typically use km/h, reflecting local measurement conventions. The underlying radar gun data is the same; it is simply displayed in the locally preferred unit. This is why a conversion tool is essential when comparing player statistics from different Grand Slam sources.