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Gear ratio calculator

Gear ratio calculator

Calculate gear ratio, output speed, theoretical loss-free output torque and rotation direction for a simple gear pair. Inputs, formula and interpretation are separated so you can verify the result before using it for a configurable part.

Calculate

Calculate gear ratio, output speed, theoretical loss-free output torque and rotation direction for a simple gear pair
Inputs: Driver teeth
Inputs: Driven teeth

Schematic illustration – not to scale.

Gear ratio calculatorSchematic illustration – not to scale. Driver teeth, Driven teeth i = z2 / z1m, z, d

Schematic illustration – not to scale.

Formula

i = z2 / z1

The formulas assume standard spur gears with the same module and no profile shift.

Step by step

  1. Enter the measured or planned values with their units.
  2. Check the formula with substituted values in the result area.
  3. Copy the parameters or open a related product for configuration.

Complete worked example

Worked example with typical workshop values: insert the inputs, apply i = z2 / z1 and compare the result with the reference table.

23060 mm
14040 mm
32060 mm

Assumptions and limitations

  • The formulas assume standard spur gears with the same module and no profile shift.

Common input mistakes

  • Decimal comma and point are accepted, but do not type units into numeric fields.
  • For gears, the tooth count must be a whole number in practice.

FAQ

Do two gears need the same module?

Yes, meshing spur gears normally require the same module.

Can I manufacture directly from this result?

Use the value as a calculation and configuration aid. Loaded or standards-critical parts need engineering review.

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