Gear Ratio
GR = Tdriven / TdriverGear Ratio Calculator
Calculate gear ratio from teeth or RPM, then estimate output speed and torque. Supports simple, compound, diameter, and planetary gear systems.
Methodology, sources & limitations
This calculator uses a published formula and the values entered in the calculator to generate the result.
- Formula
- GR = Teeth_driven / Teeth_driving = Speed_in / Speed_out
- Jurisdiction & units
- Intended for US, IN, EU, GB, AU, CA. Supports both units where applicable.
- Assumptions & limitations
- Results are preliminary estimates based on the inputs you provide. Confirm material properties, loads, local codes, and final designs with a qualified professional.
- Review status
- Formula and automated QA completed August 13, 2026; independent professional review is pending. Next scheduled review: November 13, 2026.
Validation sources
- AGMA Standards
- ISO 6336
Gear Ratio Calculator — Answer & Method
Calculate gear ratios, output speed, and torque for gear trains.
Formula: Gear Ratio
GR = Teeth_driven / Teeth_driving = Speed_in / Speed_out
GR = Gear Ratio
Example Calculation
20-tooth driving 60-tooth gear: ratio 3:1, torque multiplied by 3.
Important limitation
Use this as a preliminary estimate and verify project-specific inputs, codes, and designs with a qualified professional.
Key Facts
- A gear ratio greater than 1 reduces speed but increases torque.
Sources & Validation
AGMA StandardsISO 6336
Related Calculators
Deterministic: YesAI-Generated Numbers: NoVerified: 2026-02-12
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