# Gear Speed Calculator

> Calculate gear speed step by step: N_out = N_in × T_driver ÷ T_driven.

Page: https://freecalculator.tech/tools/gear-speed-calculator
Last reviewed: 2026-11-03

## Formula

N_out = N_in × T_driver ÷ T_driven.

- Speeds in revolutions per minute.
- Tooth counts above zero.
- No slip in gears.
- N_out = N_in × T_driver ÷ T_driven.
- Inputs used: Input speed, Driving gear teeth, Driven gear teeth.

## Inputs

- Input speed
- Driving gear teeth
- Driven gear teeth

## Worked example: 1,450 rpm motor, 20:60 gears

Reduction drive.
1. N_out = 1,450 × 20 ÷ 60 = 483.3 rpm.

## Common questions

### Can I use pulley diameters instead of teeth?

For belts, use the belt speed calculator; the speed ratio works the same way with diameters.

### What is the direction of rotation?

Two meshing external gears turn in opposite directions.

### Does load slow the output?

Gears don't slip, but the motor may slow under load; enter its loaded speed.

### How do I use the Gear Speed Calculator?

Enter the required values for Input speed, Driving gear teeth, Driven gear teeth. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

### What formula does the Gear Speed Calculator use?

N_out = N_in × T_driver ÷ T_driven. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.

### Can the Gear Speed Calculator be used for exact decisions?

Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.

## Limitations and assumptions

- Single stage.
- Ideal, rigid gears.
- Motor slip not modelled.
- Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
- The result depends on the values you enter for this gear speed calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Sources

- OpenStax (Rice University) — https://openstax.org/details/books/university-physics-volume-1

## Cite this page

- APA: Free Calculator. (2026, November 3). Gear Speed Calculator. https://freecalculator.tech/tools/gear-speed-calculator
- MLA: "Gear Speed Calculator." Free Calculator, 3 Nov. 2026, https://freecalculator.tech/tools/gear-speed-calculator.
- Link: Gear Speed Calculator — Free Calculator, https://freecalculator.tech/tools/gear-speed-calculator