How to Install a C Compiler (GCC)

Before you can run a C program, you need a compiler: the tool that turns your C code into a program your computer can run. In this lesson, you'll install GCC, the most popular free C compiler, on Windows, macOS or Linux, check that it works, and set up a comfortable code editor. It takes about 10 to 15 minutes.

What is GCC?

GCC (the GNU Compiler Collection) is a free, open-source compiler that translates C source code into machine code. It runs on Windows, macOS and Linux, and it's the compiler used throughout this tutorial. You run it from a terminal (also called the command line): a window where you type commands instead of clicking buttons.

On macOS you'll actually get Clang, a different free compiler. Apple sets things up so that typing gcc runs Clang, and for learning C the two behave almost identically.

How to install GCC on Windows

Windows doesn't come with a C compiler. The most reliable way to get GCC is MSYS2, a free package that brings GCC and other tools to Windows.

1. Go to msys2.org, download the installer and run it. Keep the default folder, C:\msys64.
2. When it finishes, open MSYS2 UCRT64 from the Start menu. A terminal window appears.
3. Type this command and press Enter, then press Y when asked to confirm:

pacman -S mingw-w64-ucrt-x86_64-gcc

4. Add GCC to your PATH so every terminal can find it. Open the Start menu, search for Edit the system environment variables, click Environment Variables, select Path under your user variables, click Edit, then New, and paste C:\msys64\ucrt64\bin. Click OK on every window.
5. Close any open terminals and open a new PowerShell or Command Prompt window. Terminals only read PATH when they start.

PATH is a list of folders Windows searches when you type a command. Adding GCC's bin folder (short for "binaries", meaning programs) is what lets you type gcc from anywhere.

How to install a C compiler on macOS

Apple provides a free set of developer tools that includes a C compiler. Open the Terminal app (press Cmd + Space and type "Terminal") and run:

xcode-select --install

A window pops up asking to install the command line developer tools. Click Install and wait a few minutes. You don't need the full Xcode app. If you see a message saying the tools are already installed, you're all set.

How to install GCC on Linux

Many Linux systems already have GCC. If not, one command installs it. On Ubuntu, Debian or Linux Mint:

sudo apt update
sudo apt install build-essential

The build-essential package includes GCC plus the C library files it needs. The word sudo runs the command as an administrator, so you'll be asked for your password. On Fedora, use sudo dnf install gcc, and on Arch, use sudo pacman -S gcc.

How do you check that GCC is installed?

Open a new terminal on any system and type:

gcc --version

On Windows with MSYS2, you'll see something like this (your version will differ):

gcc.exe (Rev2, Built by MSYS2 project) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.

On Ubuntu, the first line looks like gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0. On macOS, it mentions Apple clang version followed by a number. Any version number means success. A message like "command not found" or "not recognized" means the compiler isn't installed or isn't on your PATH yet.

Compile a test program

A version number is good; a working program is better. Create a folder for your C work, and inside it save this code in a file named check.c:

#include <stdio.h>

int main(void) {
    printf("The compiler works!\n");
    return 0;
}

In your terminal, move into that folder with cd, then compile and run the program. On macOS and Linux:

gcc check.c -o check
./check

On Windows (PowerShell):

gcc check.c -o check
.\check.exe

The compiler works!

The first command tells GCC to compile check.c and save the program (-o means "output") as check, or check.exe on Windows. The second command runs it. You'll see exactly how this works in Your First C Program.

Which code editor should you use for C?

You can write C in any plain text editor, but a code editor adds colors, auto-indenting and error hints.

This tutorial uses VS Code with its built-in terminal (View → Terminal), so you write and compile in one window.

Common mistakes when installing GCC

1. "gcc is not recognized" on Windows

If Windows says 'gcc' is not recognized as an internal or external command, the compiler's folder isn't on your PATH. Check that you added the folder that actually contains gcc.exe (for MSYS2, C:\msys64\ucrt64\bin), then close and reopen the terminal. Restarting VS Code is needed too if you use its terminal.

2. Installing the wrong MSYS2 package

Typing just pacman -S gcc installs a version meant for the MSYS2 terminal itself, not for normal Windows programs. Use the full name mingw-w64-ucrt-x86_64-gcc.

3. Forgetting ./ on macOS and Linux

Typing just check gives "command not found", because the terminal doesn't look in the current folder for programs. Type ./check, where ./ means "in this folder".

4. Running gcc in the wrong folder

If GCC says check.c: No such file or directory, your terminal is in a different folder from your file. Use cd to move to the folder where you saved check.c.

Practice exercise

#include <stdio.h>

int main(void) {
    printf("Compiler: ready\n");
    printf("Editor: ready\n");
    return 0;
}

Compiler: ready
Editor: ready

What's next?

Your computer is ready for C. Next, write and understand every line of your first C program: Hello, World!