Power transmission calculator

FRC Gear Ratio & Motor Calculator

Compare FRC motor curves, acceleration targets, compound ratios, and linked COTS gears from major robotics suppliers.

Input → stages → output

Edit any value and the drivetrain, target, and motor curves update immediately.

Calculator mode
1

Motor input

V
rpm
A
A
2

Gear stages

14.6667:1 total
%
Stage 1
T
T
Stage 2
T
T

FRC COTS gear catalog

48 results

Find gears matching the tooth counts in your stages, or browse all 476 listings from AndyMark, REV Robotics, Swerve Drive Specialties, and WestCoast Products.

ReCalc source
ManufacturerPart / SKUTeethPitchBoreProduct
AndyMarkam-074112T 20 DP 8mmView part
AndyMarkam-0741AUS12T 20 DP 8mmView part
AndyMarkam-421218T 20 DP 1/2" HexView part
AndyMarkam-353418T 20 DP 3/8" HexView part
AndyMarkam-488018T 20 DP 8mmView part
AndyMarkam-439548T 20 DP 1/2" HexView part
AndyMarkam-471448T 20 DP 1/2" HexView part
AndyMarkam-514248T 20 DP 3/8" HexView part
REV RoboticsREV-21-200012T 20 DP 8mmView part
REV RoboticsREV-21-192018T 20 DP 1/2" HexView part
REV RoboticsREV-21-193548T 20 DP 1/2" HexView part
REV RoboticsREV-21-301848T 20 DP MAXSplineView part
REV RoboticsREV-21-194466T 20 DP 1/2" HexView part
REV RoboticsREV-21-302766T 20 DP MAXSplineView part
WestCoast ProductsDIS-004212T 20 DP 8mmView part
WestCoast ProductsDIS-004312T 20 DP 8mmView part
WestCoast ProductsWCP-090112T 20 DP 8mmView part
WestCoast ProductsWCP-113612T 20 DP 8mmView part
WestCoast ProductsWCP-049312T 20 DP FalconView part
WestCoast ProductsWCP-101012T 20 DP SplineXSView part
WestCoast ProductsWCP-101112T 20 DP SplineXSView part
WestCoast ProductsWCP-134912T 20 DP SplineXSView part
WestCoast ProductsWCP-135012T 20 DP SplineXSView part
WestCoast ProductsWCP-070018T 20 DP 1/2" HexView part
WestCoast ProductsWCP-073318T 20 DP 1/2" HexView part
WestCoast ProductsWCP-209218T 20 DP 1/4" RoundView part
WestCoast ProductsWCP-209318T 20 DP 1/4" RoundView part
WestCoast ProductsWCP-043218T 20 DP 3/8" HexView part
WestCoast ProductsWCP-068218T 20 DP 3/8" HexView part
WestCoast ProductsWCP-165018T 20 DP 8mmView part
WestCoast ProductsWCP-138418T 20 DP SplineXSView part
WestCoast ProductsWCP-164118T 20 DP SplineXSView part
WestCoast ProductsWCP-013748T 20 DP 1/2" HexView part
WestCoast ProductsWCP-018148T 20 DP 1/2" HexView part
WestCoast ProductsWCP-018848T 20 DP 1/2" HexView part
WestCoast ProductsWCP-011448T 20 DP 3/8" HexView part
WestCoast ProductsWCP-108948T 20 DP SplineXLView part
WestCoast ProductsWCP-119848T 20 DP SplineXLView part
WestCoast ProductsWCP-014266T 20 DP 1/2" HexView part
WestCoast ProductsWCP-017166T 20 DP 1/2" HexView part
WestCoast ProductsWCP-143066T 20 DP 1/2" HexView part
WestCoast ProductsWCP-109866T 20 DP SplineXLView part
WestCoast ProductsWCP-120766T 20 DP SplineXLView part
AndyMarkam-414612T 20 DP Falcon SplineView part
AndyMarkam-562812T 20 DP Kraken SplineView part
AndyMarkam-563318T 20 DP Kraken SplineView part
REV RoboticsREV-21-401212T 20 DP 15T SplineView part
REV RoboticsREV-21-400818T 20 DP 15T SplineView part

Ratios use actual tooth counts. Check the linked product page for pressure angle, availability, and modified center-distance spacing.

3

Motion target and results

rpm
Entered ratio
14.6667:1
Predicted speed
301.91 rpm
Speed vs. target
+0.6%
Efficient ratio
14.811:1
Motor at target
4,443.36 rpm · 39.1 A
Required power / motor
362 W · 76.9% peak
Efficient point for the required power
Selected the higher-speed, lower-current point: 74.1% of free speed, 25.9% of stall torque, 77.2% modeled efficiency, and 39.1 A per motor.

Drivetrain and Custom motor performance

RPM and torque through each shaft, followed by the interpreted motor curves.

4,443.36 rpm · 39.1 A

Motor input

4,428.02 rpm

0.58 lbf·ft

12T → 48T
4:1

Shaft 1

1,107.01 rpm

2.25 lbf·ft

18T → 66T
3.667:1

Mechanism output

301.91 rpm

8 lbf·ft

01,5003,0004,5006,000 Motor speed (rpm) 100% 0%
Entered stages Efficient required-power solution Efficient continuous band 90%+ peak power · transient Low-speed stall risk Torque · 3 N·m stall Current · 145 A stall Power · 471 W modeled peak Efficiency · 87% modeled max

Most efficient solution for the required power

The movement needs 341 W at the output. With 94.1% drivetrain efficiency, each motor must deliver 362 W at its shaft. The calculator selects the higher-efficiency of the two motor-curve points that produce this power.

Efficient solution
Motor speed
4,443.36 rpm · 74.1%
Current per motor
39.1 A
Motor efficiency
77.2% · 89% of max
Required shaft power
362 W · 76.9% peak
Ratio for desired speed
14.811:1

Estimated electrical input at this point is 469 W per motor · 469 W total at nominal voltage. This is the steady-state power for the entered speed and torque; acceleration requires additional power.

The curves are an engineering estimate, not a thermal or controller simulation. A breaker rating is not a motor-current cap; brief current can exceed that rating before a time-dependent trip. Battery or supply sag, configured controller limits, commutation, temperature, friction, and manufacturing variation change real performance.

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Quick answer

How this frc gear ratio calculator works

FRC mode combines motor endpoint presets with compound gearing, acceleration targets, current and efficiency curves, and a linked catalog of purchasable gears. It helps teams compare ratios before committing to gearbox hardware.

How to use the calculator

  1. 1Choose an FRC motor preset or enter custom motor specifications and select the number of motors.
  2. 2Enter a direct output target or switch to linear or angular acceleration inputs for the mechanism.
  3. 3Build the proposed gear stages and compare them with the efficient ratio calculated from the required power.
  4. 4Open the COTS catalog to find matching tooth counts, diametral pitch, bores, manufacturers, SKUs, and vendor links.

Worked example

FRC drivetrain reduction check

Inputs
A 6,000 rpm-class motor drives a mechanism through a two-stage 12:1 reduction before drivetrain losses.
Result
Ideal no-load mechanism speed = 500 rpm.

The calculator then places the required loaded operating point on the selected motor curves and reports current, power, efficiency, and output error.

Common questions

What to know before using the result

Does a 40 A breaker prevent an FRC motor from drawing more than 40 A?
No. Breaker response is time-dependent and brief motor current can exceed its rating. Only enable the calculator’s current cap when modeling a controller limit you intend to configure.
Which FRC motors are included?
The selectable presets include current commonly used FRC motors such as Kraken X60, Kraken X44, NEO, NEO Vortex, Falcon 500, and other documented options, while custom motor input remains available.
Can the calculator find real FRC gears?
Yes. The collapsible catalog can filter linked gear listings from AndyMark, REV Robotics, Swerve Drive Specialties, and WestCoast Products against the entered stages.

Formula

F = ma + Fᵣ · T = Fr · P = Fv · GR = ∏(N driven ÷ N driver)

Linear mode uses F = ma and drive radius; angular mode uses τ = Iα plus resisting torque. Multiply each gear-stage ratio for total reduction; required motor-shaft power also includes drivetrain losses.

Engineering references

Assumptions and limits

  • Each listed row represents one external gear mesh between a driver and a driven gear.
  • Gears on the same compound shaft rotate at the same speed and do not add another mesh.
  • Torque excludes bearing, windage, lubrication, and other losses beyond the entered mesh efficiency.
  • Required power is the steady-state power at the entered speed and torque; acceleration requires additional power and energy.
  • Linear acceleration mode assumes constant acceleration from rest, constant drive radius, no wheel slip, and the entered resistance force. Its displayed power is the instantaneous mechanical output required at target speed.
  • Angular acceleration mode assumes constant acceleration from rest, fixed rotational inertia, and the entered resisting torque.
  • Motor curves are ideal constant-voltage approximations from entered or published free-speed, free-current, stall-torque, and stall-current endpoints.
  • No current cap is applied by default. The optional cap represents a configured motor-controller setting, not a branch-breaker rating.
  • Breaker trips are time- and temperature-dependent; battery sag, controller mode, current limiting, temperature, and manufacturing variation change real motor performance.
  • Pitch, pressure angle, tooth form, center distance, and interference must be checked separately.
Educational estimate
Use this result for learning and early design exploration. Verify safety-critical or production decisions with the governing standard, material data, real tooling, and a qualified engineer.

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