CNC Tools & Calculators

Free online tools for CNC machinists, programmers, and hobbyists.

G-Code Reference Guide

Complete reference for G-code and M-code commands used in CNC machining. Each command includes a description, syntax, and example.

Reference G-Code

Tap & Drill Size Chart

Complete tap drill chart for UNC, UNF, and Metric threads with tap drill sizes, decimal equivalents, and clearance drills.

Drilling Tapping

SFM Calculator

Convert between surface feet per minute (SFM) and RPM for any tool diameter. Includes recommended surface speeds for 20+ materials.

Speeds RPM

Chipload Calculator

Calculate CNC feed rate from chipload, RPM, and flute count — or find chipload from your current parameters. Includes recommended chiploads for 17 materials.

Feed Rate Chipload

Stepover Calculator

Calculate cusp height from ball nose stepover and tool diameter. Visual diagram shows scallop profile for any stepover percentage.

Ball Nose Surface Finish

Need to verify your G-code?

Use CutViewer to visualize toolpaths in 3D before running them on your machine.

Launch CutViewer