Gear Ratio Speed Calc is a professional gear train calculator for engineers, machinists, and mechanical designers. FEATURES: - Single, dual, and triple stage gear ratio calculations - Calculate overall gear ratio, output RPM, and torque multiplier - 8 common gear presets for quick selection - Custom driver and driven teeth input for any gear combination - Supports any input RPM value - Clean, dark-themed interface for shop and field use FORMULAS: - Gear Ratio = Driven Teeth / Driver Teeth - Output RPM = Input RPM / Overall Gear Ratio - Torque Multiplier = Overall Gear Ratio - Multi-stage: Overall Ratio = Stage 1 x Stage 2 x Stage 3 PRESETS INCLUDED: 12/48 (4:1), 15/45 (3:1), 18/36 (2:1), 20/40 (2:1), 16/64 (4:1), 24/72 (3:1), 20/60 (3:1), 14/56 (4:1) Perfect for designing gear trains, verifying speed reductions, and calculating torque multiplication in mechanical power transmission systems.