Rotations per minute and wheel/tool diameter in inches—linear speed at the rim in ft/min and m/s.
Diameter is in inches; circumference in feet is π × (D÷12). Surface speed in feet per minute is circumference × RPM, then an approximate m/s line uses ft/min × 0.3048 ÷ 60. Tool/workpiece slip and unit conventions beyond the labels are not modeled.
This calculator uses plain decimal numbers. If a result looks wrong, check whether you used a comma instead of a dot (or vice versa) where the field expects one.