📜 EIP vs ERC — What’s the Difference?

If you’ve read Ethereum documentation or audited a smart contract, you’ve probably seen words like EIP-1559, ERC-20, or ERC-721.

They look similar — but they’re not the same.

Let’s break down what EIPs and ERCs mean, how they’re related, and why both are essential to Ethereum’s evolution 🔍

⚙️ What Is an EIP?

EIP stands for Ethereum Improvement Proposal.

An EIP is like a blueprint for upgrading Ethereum — it’s how developers propose changes, improvements, or new features to the network.

Think of EIPs as:

“Official documents that describe a new idea, rule, or technical change for Ethereum.”

🧱 Example: EIP-1559 (The Gas Fee Upgrade)

Before EIP-1559, gas fees on Ethereum were unpredictable — users had to guess how much to pay.

EIP-1559 changed that by introducing:

• A base fee that gets burned 🔥


• A tip (priority fee) for miners


• Better fee estimation and user experience

Result: fairer gas pricing, more stable transactions, and partial ETH burn — making ETH slightly deflationary.

📘 EIP-1559 = a change to Ethereum’s protocol itself.

💡 Types of EIPs

There are a few categories:

👉 Notice that last one?

That’s where ERCs come in.

🧩 What Is an ERC?

ERC stands for Ethereum Request for Comment.

It’s a type of EIP, but specifically focused on application-level standards — mostly smart contracts.

In short:

Every ERC is an EIP, but not every EIP is an ERC.

ERCs define rules and interfaces that make contracts work together across the Ethereum ecosystem.

🪙 Example: ERC-20 (Fungible Token Standard)

This defines how fungible tokens (like stablecoins or governance tokens) behave.

Common functions:

function totalSupply() public view returns (uint256);

function balanceOf(address account) public view returns (uint256);

function transfer(address recipient, uint256 amount) public returns (bool);

Any token that follows these rules (like USDC, UNI, DAI) can easily interact with wallets, DEXs, and DeFi protocols.

📘 ERC-20 = EIP that defines a token standard for smart contracts.

🎨 Example: ERC-721 (NFT Standard)

The standard that made NFTs possible!

Defines unique, non-fungible assets — each token has its own ID.

Example projects:

• Bored Ape Yacht Club


• CryptoPunks


• Art Blocks

ERC-721 is also an EIP, but it focuses on NFTs, not protocol upgrades.

⚖️ EIP vs ERC — Key Differences

🧠 Why Auditors Should Care

As a security researcher or auditor, understanding EIPs and ERCs is critical because:

1. ERC standards define expected behavior of contracts.
   
   → If a contract claims to follow ERC-20 but behaves differently, that’s a red flag.




2. EIPs can change gas rules, opcodes, or consensus logic, affecting how you audit gas usage or L2 behavior.




3. Knowing which EIP/feature a protocol depends on helps you assess risk — especially in newer EVM chains.

🧩 Example: When auditing gas refunds or burn mechanisms, you must know if EIP-3529 (reducing gas refunds) applies.

🧬 Relationship Summary

You can think of it like this:

EIP (Ethereum Improvement Proposal)

 ├── Core EIPs (protocol upgrades)

 ├── Networking EIPs

 └── Interface EIPs → ERCs (token & contract standards)

So when you hear “ERC-20” or “ERC-721,” remember — they’re just EIPs that define standards for how smart contracts should behave.

🧩 Final Thoughts

Ethereum evolves through community proposals — EIPs and ERCs are how developers, researchers, and auditors collaborate to make it better.

• 
  EIPs shape the engine.


• 
  ERCs define the rules for the apps that run on that engine.

Understanding both helps you build, audit, and interact with Ethereum more confidently.