Is Nand2Tetris Worth It? A Complete Review for Learning Computers From First Principles

Mar 21, 2026

The Problem

I had been programming for years. I could build web applications, write APIs, and debug code in Python and JavaScript. But when someone asked me how a computer actually works, I realized I didn’t know.

What happens when my code runs? How does memory work? What’s inside a CPU? I had vague ideas but no concrete understanding. I was working with abstraction layers I had never explored beneath.

Then I found Nand2Tetris. The promise: build a complete computer system from NAND gates to an operating system. But the question kept nagging at me—is it worth the time investment?

What I Found

Nand2Tetris is consistently recommended as one of the best ways to learn how computers work from first principles.

NAND gate → Logic gates → ALU → CPU → Computer → Assembler → VM → Compiler → OS

You start with a single NAND gate. From that, you build everything else: AND gates, OR gates, adders, the ALU, registers, RAM, the CPU, assembler, virtual machine, compiler, and operating system.

The course is free. It takes approximately 100 hours for the complete experience. And it requires no prerequisites beyond basic programming in any language.

What You Actually Build

The course has 12 projects. Each project builds on the previous one:

┌─────────────────────────────────────────────────────────────────┐
│                     Nand2Tetris Projects                        │
├─────────────────────────────────────────────────────────────────┤
│  1-2: Logic gates from NAND     │ Boolean algebra, combinational│
│  3: ALU (Arithmetic Logic Unit) │ Binary arithmetic, CPU core   │
│  4: Memory (RAM)                │ Sequential logic, stored state│
│  5: Computer architecture       │ CPU design, instruction set   │
│  6: Assembler                   │ Machine code, translation     │
│  7: Virtual Machine             │ Stack-based architecture      │
│  8: Compiler                    │ High-level to VM translation  │
│  9-12: Operating System         │ Syscalls, memory management   │
└─────────────────────────────────────────────────────────────────┘

I tried just Part 1 first—the hardware projects. That took about 50 hours. I built the ALU, memory, and CPU from scratch. The moment I ran my first program on a computer I had built from logic gates was the moment I truly understood what “stored program” means.

Why It’s Worth It

Immediate Benefits

After completing Nand2Tetris, several things changed:

Debugging became clearer—I understood stack traces and memory errors because I had built the memory model myself
Performance made sense—Cache behavior and memory access patterns weren’t mysterious anymore
Interview confidence improved—Questions about CPU, memory, and compilers became answerable
Advanced topics became accessible—Operating systems and compilers weren’t intimidating

The Time Investment

Part 1 only (~50 hours) → Hardware + Assembler
Full course (~100 hours) → Complete system
With extensions (~150 hours) → Jack language ecosystem

I spread Part 1 over two months, working about 6-8 hours per week. That’s a reasonable commitment for something that fundamentally changed how I understand computing.

What Makes It Different

Most resources teach you about computers. Nand2Tetris makes you build one. The difference is significant:

Textbooks explain concepts → You read, maybe understand
Nand2Tetris forces you to implement → You build, you get it

Each project has test suites. Your implementation either passes or fails. When it fails, you debug until you understand why.

What You Build (Examples)

Project 1: Logic Gates from NAND

I started with just NAND and built everything else:

CHIP And {
    IN a, b;
    OUT out;

    PARTS:
    Nand(a=a, b=b, out=n);
    Not(in=n, out=out);
}

This taught me that all boolean logic can be built from a single primitive. The elegance surprised me.

Project 3: Memory

I built a single bit of memory, then scaled it up:

CHIP Bit {
    IN in, load;
    OUT out;

    PARTS:
    Mux(a=out, b=in, sel=load, out=mux);
    DFF(in=mux, out=out);
}

Then I built registers, RAM8, RAM64, RAM512, RAM4K, and finally RAM16K. By the end, I understood exactly what “memory address” means.

Project 5: The CPU

This is where everything clicked:

CHIP CPU {
    IN inM[16],         // Memory data input
        instruction[16], // Instruction to execute
        reset;
    OUT outM[16],       // Memory data output
        writeM,          // Write to memory?
        addressM[15],    // Memory address
        pc[15];          // Program counter

    PARTS:
    // ALU, registers, control logic
    // You implement this entire thing
}

Building the CPU taught me the fetch-decode-execute cycle in a way no textbook could.

Project 6: Assembler

I wrote a program that converts assembly language to machine code:

# Input (assembly):
@R0
D=M
@R1
D=D-M

# Output (binary):
0000000000000000
1111110000010000
0000000000000001
1111010011010000

This made me understand what compilers and assemblers actually do.

Common Mistakes to Avoid

Mistake 1: Rushing Through Projects

I almost made this mistake. I got some projects working but couldn’t explain my code. I went back and reworked them.

If tests pass but you can’t explain your implementation, you’re not ready for the next project. Each project is a prerequisite for the next.

Mistake 2: Skipping Hardware Projects

Some people want to jump to the software projects. This defeats the purpose. The CPU design understanding you get from projects 1-5 is essential for understanding what your compiler generates.

Mistake 3: Comparing Hack to Real Systems

The Hack platform is intentionally simplified. It’s not x86 or ARM. Don’t compare it to production systems—compare the concepts.

What you learn about instruction sets, memory, and compilation transfers directly to real architectures.

Mistake 4: Going It Alone

I got stuck several times. The course forums and community discussions saved me. Use them.

Mistake 5: Stopping After the Compiler

Projects 9-12 (the OS) tie everything together. Don’t stop at project 8.

Who Should Take This

You Should Take Nand2Tetris If…	Skip If…
You can code but don’t understand what happens underneath	You’re completely new to programming
You want to work in embedded, games, or systems	You only want to do web development
You have 50-100 hours to invest	You need immediate practical skills
You enjoy building things from scratch	You prefer theory to hands-on work

Summary

In this post, I explained why Nand2Tetris is worth the investment. The key points:

100 hours for the complete experience—50 hours for hardware only
Build everything from NAND gates to OS—true first-principles learning
Free with no prerequisites—accessible to anyone who can program
Immediate and long-term benefits—debugging, performance, career paths
Hands-on every step—no passive watching, you implement everything

The path: Start with NAND, build logic gates, then ALU, then memory, then CPU, then assembler, then VM, then compiler, then OS. Each layer teaches you something fundamental about how computers work.

Final Words + More Resources

My intention with this article was to help others share my knowledge and experience. If you want to contact me, you can contact by email: Email me

Here are also the most important links from this article along with some further resources that will help you in this scope:

Oh, and if you found these resources useful, don’t forget to support me by starring the repo on GitHub!