---
title: "Will a Machine Shop Test My G-Code Knowledge?"
description: "Many shops do test your code knowledge when hiring, through a short quiz, a program to read, or questions at the machine. Here is what to expect and how to be ready."
url: https://gcodepractice.com/journal/will-a-machine-shop-test-my-g-code-knowledge/
canonical: https://gcodepractice.com/journal/will-a-machine-shop-test-my-g-code-knowledge/
author: "Lawrence Arya"
authorUrl: https://www.linkedin.com/in/vibecoding/
published: 2026-06-02
updated: 2026-06-02
category: "Practice"
tags: ["hiring", "interview", "g-code", "test prep"]
lang: en
---

# Will a Machine Shop Test My G-Code Knowledge?

> **TL;DR** Many machine shops do test your G-code knowledge when hiring, but rarely with a hard written exam. It is usually a short quiz, a program printout to read and explain, or questions at the machine. They are confirming you can read a program safely before trusting you with one. Fluent recall of the common codes is what makes that test a non-event.

It is a reasonable thing to wonder before an interview, and the honest answer is that many shops do test your G-code knowledge, just rarely in the way people fear. There is usually no hard written exam. It is a short, practical check that you can read a program before they trust you with one.

## How shops usually test it

- **A short quiz.** A handful of code questions, on paper or verbally.
- **A program to read.** They hand you a printout and ask what it does, block by block.
- **Questions at the machine.** Pointing at a line and asking you to explain it.

The depth scales with the role: an operator role checks the common codes; a setter or programmer role goes into offsets, compensation, and cycles.

| Role | Likely depth |
| --- | --- |
| Operator | Read common codes, explain a block |
| Setter | Offsets, tooling, full-program reading |
| Programmer | Compensation, cycles, writing code |

## How to make it a non-event

Whatever form it takes, the test rewards fluent reading, which is recall you can build in advance. Drill the [common G-codes](/journal/common-g-codes-for-cnc-beginners/) and [common M-codes](/journal/common-m-codes-for-cnc-beginners/) with [beginner CNC code practice](/journal/beginner-cnc-code-practice/), and for worked examples see [CNC practical test examples for a job interview](/journal/cnc-practical-test-examples-for-job-interview/) and [how to read a G-code print for an interview test](/journal/how-to-read-a-g-code-print-for-an-interview-test/). A free tool like [G-Code Sprint](/g-code-practice/) makes the reading automatic.

## Bottom line

Yes, many shops test your G-code knowledge, usually with a short quiz, a program to read, or questions at the machine, scaled to the role. Build fluent recall of the common codes and that test becomes the easy part of the interview.

## Sources

- [NIMS (National Institute for Metalworking Skills)](https://www.nims-skills.org/)
- [LinuxCNC G-code reference](https://linuxcnc.org/docs/html/gcode/g-code.html)
- [CNCCookbook: G-code and M-code cheat sheet](https://www.cnccookbook.com/g-code-m-code-cnc-list-cheat-sheet/)

## Frequently asked questions

### Do machine shops test G-code knowledge when hiring?
Many do, though usually informally: a short quiz, a program to read and explain, or questions at the machine. They are confirming you can read a program safely, not giving a hard written exam. The level depends on the role.

### What kind of G-code test does a shop give?
Commonly reading a short program and saying what it does, identifying common codes, and the standard comparisons like `G00` vs `G01`. For setter or programmer roles it goes deeper into offsets and cycles.

### How do I pass a shop's G-code test?
Make reading automatic by drilling the common codes for recall. A free tool like G-Code Sprint builds that fluency, so whatever form the shop's test takes, the code questions are the easy part.

*G-Code Sprint is a study and practice tool only. Always follow your instructor, employer, machine manual, and shop safety procedures.*

---

Source: https://gcodepractice.com/journal/will-a-machine-shop-test-my-g-code-knowledge/
Author: Lawrence Arya — https://www.linkedin.com/in/vibecoding/