Spur Gear Generator

Design the gears your project needs with our free gear generator

There are makers out there that are using better tools than ever to route, 3D print, waterjet, laser cut, and machine different gears. We’ve combined some of our best code using modern software to build this simple, free, and robust online tool. Just what you need to get your spur gear project started today.

Free Gear Generator - Evolvent Design


This calculator generates the .DXF and .SVG files for making external spur gears, rack and pinion sets, and internal spur gears. DXF files are accepted by most machines that cut 2D shapes such as CNC wood routers, laser cutters, waterjets, and CNC plasma tables. A DXF is also the starting point for various CNC machines that require CAM software. Standard spur gear calculations, graphics, and .DXF files have never been more accurate, accessible, or easy. Involute tooth form only. Clocks use the cycloidal or triangular tooth forms.

External spur gear generator

n > 0, External Spur Gear

gear rack generator

n=0, Gear Rack

internal spur gear generator

n <0, Internal Spur Gear

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Using an involute gear cutter to mill a gear

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Spur Gear Calculator Online

To calculate a spur gear, simply decide and input your tooth count, gear module, and pressure angle and the online spur gear DXF generator will do the rest. A spur gear calculator uses these parameters to generate the involute tooth form that's the right size and shape to take into your CAD software, or straight to a CNC router or laser cutter.

The live output lets you visualize your spur gear to ensure you have the right fit and to manage the undercut and gear size, while the .DXF and .SVG outputs will fit into your CAD software or graphics software. If you're looking to make the right gear blank for your gear, you can use our free Gear Dimension Calculator to find the key dimensions of your external spur gear.

How to Use a Spur Gear Generator

  • Input the following parameters in our free gear dxf generator:

Tooth Count – is set with the parameter "n" for Gear 1 and Gear 2

Gear Type – External spur gears use a positive tooth count, while internal spur gears use a negative tooth count. For a rack and pinion, set n=0. The rack length defaults to the diameter of Gear 2.

Module (Pitch) – this parameter sets the tooth size. To convert, use: Module = 25.4 / Diametral Pitch

Profile Shift – Default is 0 for most applications. A positive profile shift represents a theoretical cutter cutting deeper (leaving longer, thinner teeth), while a negative shift would cutter more shallow (leaving shorter, thicker teeth). Another way to think about it is positive profile shift numbers will allow for more backlash between two gears en-mesh.

Center Hole Diameter – Central bore hole in each gear, for standard size we’d recommend the Machinery's Handbook. Gear 1 and Gear 2 can have the same or different center hole diameters.

Center Distance – This is the distance between the two shaft centers holding the gears.

Making Gears with a DXF or SVG

Spur gears can be used in a wide variety of applications. Having a DXF or SVG file for your gear is the first step to building your new gear project. After you have your 2D model of your spur gear, you can use this file for a range of applications.

  - Make wooden gears on your CNC router

  - Laser cut gears out of wood or thin metal

  - 3D Print gears for prototyping

  - 2D or 3D modeling of gears for different simulations

  - Understanding how gears work / why gears roll so well

  - Start with a 2D sketch in SolidWorks, Fusion 360, Inventor, Revit, Onshape, SketchUp to buildup 3D gears

spur gear dxf svg - Evolvent Design

Spur Gear Design

One of the more common mistakes we see in simplified gear software is the lack of undercut in small tooth count gears. This can make gears bind or function poorly. We also see low resolution involute shapes that could function better if they had the correct geometry with sufficient data points defining the involute.

Being members of the American Gear Manufacturers Association (AGMA) and having manufactured gears in most plastics and metals, the details count. So we put the same attention to detail and mathematical skill to work for everyone. For measuring and inspecting gears, using a Measurement Over Pins Calculator is one of the best methods to ensure your gears are perfectly in-spec.

Pro-Tip! Notes for the wood shop or anyone using an endmill to make the cut:
The bit size is a very important consideration! Depending on your software, if the cutter is too large it will either over-cut the root and weaken the tooth, or leave a radius and not finish the involute profile or undercut. When using your CAD program, compare the cutter diameter to the gear's root space to make sure it's small enough and has some clearance

What is a spur gear used for?

Spur gears transmit power through parallel shafts. The ratio of tooth count between two gears changes the relative speed of those gears by that ratio. Spur gears can increase or decrease the speed of a mechanical system, increase or decrease its available torque, or change direction from forward to reverse.

What is the module of a spur gear?

The module of a gear controls its size. Module is the ratio of the reference diameter divided by the number of teeth; so that a gear with a larger module will have a larger diameter. Small module gears (0.1-0.5) are found in watches and clocks, while larger module (1+) may be found in machine transmissions.  More here


Here's a Quick Summary:

› Simple and free gear generator

› Input tooth count, module, and pressure angle

› Export .DXF, .SVG files