Tiny Online Tools
The CNC Toolpath Analyzer reads a milling or router G-code program and reports the numbers that matter before you cut real material: feed rates, spindle speeds, how much of the program is actually cutting versus moving in rapid, an estimated machining time, a per-tool breakdown, and the depth-per-pass profile — the Z levels the program visits, in the order it visits them.
Drop in a .nc, .ngc, .tap, .gcode or .g file from Fusion 360, Carbide Create, VCarve, LinuxCNC or any grbl-compatible post processor. The analyzer measures cutting distance versus rapid distance directly from the file's G0 versus G1/G2/G3 moves, reports the feed-rate range used by cutting moves as a distance-weighted histogram, and reads spindle speed and direction from M3/M4/M5 and their S values — including the common compact style where the spindle speed is written on the same line as the rapid move that precedes it (G0 X0 Y0 S15000 M3).
For multi-tool jobs, the Tools tab breaks cutting distance, rapid distance and time down per tool number, and lists every tool change (T word and M6) with its line number. The Passes tab lists every distinct Z depth the program cuts at, in the order the program first reaches it — a practical view of a roughing-then-finishing strategy without guessing at the CAM software's intentions.
Machining time is an estimate, and the tool says so plainly: it sums distance ÷ feedrate for every cutting move using the program's own commanded feed, but G-code carries no feedrate word for rapid (G0) moves — the controller decides that speed — so you tell the analyzer what rapid speed to assume, and it is clearly labelled as an assumption, not a measurement. There is no acceleration model here, unlike the site's FDM G-code Analyzer: a milling program states no machine acceleration limits to model with, and a straightforward feed/distance estimate is the honest option for a first-pass time check.
Export the full report as JSON, or the depth-per-pass table as CSV, for your own records or CAM comparisons. Pair it with the CNC G-code Viewer to see the same program's toolpath rendered in 3D. Everything runs locally in your browser — the file never leaves your machine.