How many tennis balls do you actually need?
Tennis balls lose internal pressure and surface fuzz with use, which changes their bounce and speed. This calculator gives a practical estimate of how many cans of balls you should budget for based on how much you play and how quickly you like to retire balls.
How the estimate is calculated
The calculator multiplies your weekly playing hours by an average of 4.345 weeks per month to get total monthly hours, then divides that by an assumed number of hours a can of balls stays usable at your chosen level: about 6 hours for casual/recreational play, 3 hours for regular club play, and 1.5 hours for competitive or tournament-standard play where balls are refreshed much more often (many tournaments change balls every 9 games).
Each can is assumed to contain 3 balls, which is the standard packaging for new tennis balls.
These are general planning estimates – actual ball life varies with surface type, ball brand, altitude, and how hard you hit, so treat this as a helpful budgeting guide rather than an exact requirement.