Mechanical & Drives
Gear ratio, speed and torque calculator
Output speed and torque from tooth counts and input.
Calculating…
How it's calculated
Ratio = Z_driven ÷ Z_driver
n_out = n_in ÷ ratio
T_out = T_in × ratio × η
The same calculation works for sprockets and timing pulleys. Typical efficiency per stage: spur and helical gears 97–99%, chain 95–98%, worm gears 50–90% depending on ratio.
For multi-stage gearboxes, multiply the stage ratios and the stage efficiencies.