How to use the gear ratio calculator
Compute gear ratio, output speed and torque multiplication. Enter driver gear teeth, driven gear teeth, driver speed, driver torque in the fields above; the gear ratio, output speed, output torque are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- N1 — Driver gear teeth
- N2 — Driven gear teeth
- rpm1 — Driver speed (rpm)
- T1 — Driver torque (N·m)
Worked example
With driver gear teeth = 20, driven gear teeth = 60, driver speed = 1500 rpm, driver torque = 10 N·m, the calculator gives gear ratio ≈ 3; output speed ≈ 500 rpm; output torque ≈ 30 N·m.
Frequently asked questions
What is the formula for the gear ratio calculation?
Gear ratio = N2 / N1. Output speed (rpm) = rpm1 / [Gear ratio]. Output torque (N·m) = T1 × [Gear ratio]. Here N1 is driver gear teeth, N2 is driven gear teeth, rpm1 is driver speed (rpm), T1 is driver torque (N·m).
What inputs do I need for the gear ratio calculator?
You need driver gear teeth, driven gear teeth, driver speed in rpm, driver torque in N·m. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.