Free online G-code viewer
Last updated: 21 October 2026
DIMview draws the toolpath of a G-code file in 3D in your browser. It is a quick way to see what a CNC program or a printer file is going to do before it reaches the machine, with nothing to install and no upload.
Open a G-code file
- Open DIMview with the button below.
- Drag the file onto the page, or press the open area and choose it.
- The toolpath appears over a grid. Orbit by dragging, zoom with the wheel and pan with the right mouse button.
The recognised extensions are .gcode, .nc, .mpf, .ngc, .cnc, .tap, .inp and .iso. DIMview reads the file with its own parser, so the toolpath includes straight moves and arcs.
What you can do with a toolpath
- Step through the depths. The Z slider shows the toolpath only up to the height you choose. Drag it from the top down to watch a milling program go deeper pass by pass, or a printer file build up layer by layer.
- Show or hide rapid moves. The Travel button switches the positioning moves on and off, so you can look at the cutting path alone or check where the tool travels between cuts.
- Look from every side. Orbit around the toolpath to check it from the top, the front or the side.
A quick check before the machine runs
A viewer cannot replace a simulation with the real stock and tool, but it catches the mistakes that are easy to see: a program in the wrong place, a move that goes far outside the part, a depth that is too deep or too shallow, or a missing pass. Compare the extent of the toolpath with the size of your stock before you load the program on the machine.
Privacy
The program is read by your browser and is not uploaded. G-code often contains the geometry of a customer part, and with DIMview it stays on your device. Our visitor statistics count page views without cookies and never see the file (privacy policy).
What DIMview does not do
DIMview does not simulate material removal, check for collisions, estimate machining time or edit the program. It shows the path that the code describes.
Questions
Is the G-code viewer free?
Yes. There are no ads, no account and no time limit.
Does it work for 3D printer G-code too?
It reads the same kind of files, so a sliced printer file opens and the Z slider steps through its layers. It does not show filament, temperatures or print time.
My file did not open. What can I check?
Make sure it is a plain text program and not a binary or zipped file. Files that carry a CNC extension but contain something else are not accepted.