Best Open-Source CNC Software 2026: 6 Options Compared

Open-source CNC software lets you build a controller, a toolpath chain and a simulator without a license from anyone. The pieces fit together in a predictable order. FreeCAD models the part and generates toolpaths in its CAM workbench. CAMotics then simulates the G-code in 3D, which shows collisions and gouges before you waste material. A sender such as Universal G-code Sender streams the file to a GRBL-class controller, or LinuxCNC takes over as the controller itself, running on a dedicated Linux PC to drive larger machines with real-time control. The trade-off is that you assemble this chain yourself, and the stages do not share a project file. Each export is a place where units, origins and tool numbers can drift, so write down your conventions and run every program through the simulator. LinuxCNC is the heavyweight option with the most setup work, and it needs hardware that meets its real-time requirements. A sender is far lighter and suits a desktop router with a GRBL controller. None of these ships a library of machine-specific post-processors the way commercial CAM does, so expect to adapt one from a similar machine when your controller is unusual.

FreeCAD

LGPL-2.1 modeler with a CAM workbench for generating toolpaths. Free of conditions, but you will spend time learning its workbenches.

Price: Free (Free, no sign-up) (FreeCAD pricing, checked 2026-10-22).

Platforms and license: Windows, macOS, Linux. LGPL-2.1 (open source) (license source).

Project activity: 34.9k GitHub stars · latest release 1.1.4 (Sep 28, 2026) · last commit Oct 27, 2026

Best for: Modeling and toolpaths.

Worth knowing: Mainly parametric 3D; 2D drafting is not its strength.

CAMotics

Open-source G-code simulator under GPL, running on Linux, macOS and Windows. Simulates only; no toolpath generation or machine control.

Price: Free (Open-source and free, per camotics.org) (CAMotics pricing, checked 2026-10-24).

Platforms and license: Windows, macOS, Linux. GPL-2.0-or-later (open source) (license source).

Project activity: 763 GitHub stars · latest release 1.2.0-release (Feb 9, 2019) · last commit Mar 23, 2026

Best for: Previewing G-code.

Worth knowing: G-code simulator that shows tool paths in 3D; it does not generate toolpaths or run the machine.

Universal G-code Sender

GPL-3.0 Java sender for GRBL-class controllers. Streams code and jogs the machine; the G-code comes from another program.

Price: Free (Free and open source) (Universal G-code Sender pricing, checked 2026-10-24).

Platforms and license: Desktop. GPL-3.0 (open source) (license source).

Project activity: 2.3k GitHub stars · latest release v2.1.27 (Sep 10, 2026) · last commit Oct 25, 2026

Best for: Desktop routers with GRBL.

Worth knowing: Java G-code sender for GRBL-class controllers; README lists Windows downloads and other platform packages.

LinuxCNC

GPL-2.0 machine controller that runs on Linux. Full control software for larger machines, with more setup work than a sender.

Price: Free (Free; source under GNU GPLv2 per the home page) (LinuxCNC pricing, checked 2026-10-24).

Platforms and license: Linux. GPL-2.0 (open source) (license source).

Project activity: 2.5k GitHub stars · latest release v2.10.0-pre2 (Sep 28, 2026) · last commit Oct 27, 2026

Best for: Machines needing a real controller.

bCNC

GPL-2.0 Python program combining a GRBL sender, autoleveler, G-code editor and basic CAM on Windows, Linux and Mac. A single window for small jobs, with a dated interface.

Price: Free (Free and open source) (bCNC pricing, checked 2026-10-24).

Platforms and license: Windows, macOS, Linux. GPL-2.0 (open source) (license source).

Project activity: 1.8k GitHub stars · latest release pypi (Mar 27, 2025) · last commit Oct 27, 2026

Best for: All-in-one sender and editor.

Worth knowing: README: GRBL sender, autoleveler, g-code editor, digitizer and basic CAM in one cross-platform Python program (Windows, Linux, Mac).

Grbl

GPL-3.0-or-later controller firmware that runs on an Arduino with a 328p processor and accepts standard G-code. Firmware rather than desktop software, so you still need a sender.

Price: Free (Free and open source firmware) (Grbl pricing, checked 2026-10-24).

Platforms and license: Arduino (ATmega328p). GPL-3.0-or-later (open source) (license source).

Project activity: 4.6k GitHub stars · latest release v1.1h.20190825 (Aug 26, 2019) · No commits since Jun 12, 2024

Best for: Cheap hobby controller boards.

Worth knowing: README: motion controller written in C that runs on an Arduino with a 328p processor and accepts standard G-code. Firmware, not desktop software.

Which one to pick

• You need to see the cut before you make it: CAMotics
• You run a hobby router with GRBL: Universal G-code Sender
• You want to drive a mill or lathe from a Linux PC: LinuxCNC