If you’ve ever bought a token like USDT, UNI, or AAVE on Ethereum, you’ve already used an ERC20 token – even if you didn’t know it. ERC20 is the technical standard that defines how most tokens on the Ethereum blockchain behave. It’s the reason tokens can be sent, received, and traded seamlessly across wallets, exchanges, and decentralized applications.
In this guide, we’ll break down everything you need to know about ERC20 tokens: what they are, how transfers work, why gas fees matter, and how they compare to other token standards. Whether you’re a crypto beginner or an experienced investor, understanding ERC20 is essential for navigating the world of DeFi, NFTs, and tokenized assets.
➡️ Recommended reading before you dive in
📋 What you'll learn
- 1. What Is ERC20? The Simple Definition
- 2. How ERC20 Tokens Work (The Technical Part Made Simple)
- 3. ERC20 Transfers Explained – Sending Tokens Step by Step
- 4. Why Gas Fees Are Different for ERC20 Transfers
- 5. ERC20 vs ERC721, ERC1155, and BEP-20
- 6. Most Common ERC20 Tokens (Real‑World Examples)
- 7. How to Store and Manage ERC20 Tokens
- 8. Security Risks and How to Avoid Them
- 9. Can You Create Your Own ERC20 Token?
- 10. The Future of ERC20 and Ethereum Upgrades
- 11. Frequently Asked Questions
What Is ERC20? The Simple Definition
ERC20 stands for Ethereum Request for Comment 20. It’s a set of rules that every token on Ethereum should follow. Think of it as a template: if a token creator follows this template, their token will work seamlessly with all Ethereum wallets (like MetaMask), exchanges (like Uniswap), and smart contracts.
💡 Why ERC20 matters:
- Interoperability: Any ERC20 token can be stored in any Ethereum wallet.
- Liquidity: Exchanges can list new tokens quickly because they know the standard.
- DeFi building: Lending, borrowing, and yield farming protocols are built around ERC20.
How ERC20 Tokens Work (The Technical Part Made Simple)
Every ERC20 token is actually a smart contract on the Ethereum blockchain. That contract holds a ledger of who owns how many tokens. When you “send” tokens, you’re really calling a function in that smart contract to update the balances.
The ERC20 standard defines six mandatory functions that every token contract must implement:
totalSupply()– how many tokens exist in total.balanceOf(address)– how many tokens a specific address holds.transfer(address to, uint256 amount)– send tokens from your address to another.transferFrom(address from, address to, uint256 amount)– used by contracts to move tokens on your behalf (with approval).approve(address spender, uint256 amount)– allow another address to spend tokens from your wallet.allowance(address owner, address spender)– check how many tokens a spender is allowed to use.
These functions make it possible for decentralized exchanges (like Uniswap) to swap tokens automatically. When you trade on Uniswap, you’re calling approve and then the exchange calls transferFrom to pull the tokens from your wallet.
ERC20 Transfers Explained – Sending Tokens Step by Step
Initiating a Transfer
Wallet ActionYou open your wallet (MetaMask, Trust Wallet, etc.) and choose to send an ERC20 token. You enter the recipient’s address and the amount. Your wallet creates a transaction that calls the transfer function of the token’s smart contract.
Broadcasting to the Mempool
Network StageThe transaction is broadcast to the Ethereum network and sits in the mempool (a waiting area) until a miner includes it in a block. During this time, you can’t cancel it unless you replace it with a higher gas fee.
Confirmation and Finality
Blockchain RecordA miner includes your transaction in a block. After a few more blocks (confirmations), the network considers the transfer final. The recipient’s balance is updated, and you can see the transaction on Etherscan.
Unlike sending ETH, sending an ERC20 token requires the smart contract to execute code. That’s why it usually costs more gas than a simple ETH transfer.
Why Gas Fees Are Different for ERC20 Transfers
Gas is the fee you pay to compensate miners for the computational power needed to process your transaction. ERC20 transfers consume more gas than sending ETH because they involve running code in the token contract.
| Transaction Type | Gas Used (approx.) | Typical Cost (at 20 Gwei) |
|---|---|---|
| Simple ETH transfer | 21,000 gas | $1–$3 |
| ERC20 transfer | 45,000–65,000 gas | $2–$8 |
| Uniswap swap (ERC20 to ERC20) | 150,000–300,000 gas | $10–$40 |
Gas prices fluctuate based on network congestion. You can use tools like Etherscan Gas Tracker or wallet gas estimators to set a reasonable fee. Layer 2 solutions like Arbitrum and Optimism drastically reduce costs – learn more in our Layer 2 guide.
ERC20 vs ERC721, ERC1155, and BEP-20
ERC20 is for fungible tokens – each token is identical and interchangeable (like dollars). Other standards serve different purposes:
| Standard | Type | Use Case | Example |
|---|---|---|---|
| ERC20 | Fungible | Currencies, governance tokens, staking tokens | USDC, UNI, LINK |
| ERC721 | Non‑fungible (NFT) | Unique digital assets, art, collectibles | CryptoPunks, Bored Apes |
| ERC1155 | Multi‑token (fungible + non‑fungible) | Gaming items, hybrid collections | Enjin, Sandbox assets |
| BEP-20 | Fungible (Binance Smart Chain) | Same as ERC20 but on BSC | BNB, CAKE |
While BEP-20 is technically a copy of ERC20, it runs on Binance Smart Chain with lower fees. However, it’s less decentralized and has a different security model.
Most Common ERC20 Tokens (Real‑World Examples)
- Stablecoins: USDT (Tether), USDC (Circle), DAI (Maker) – these are the backbone of crypto trading and DeFi.
- DeFi governance: UNI (Uniswap), AAVE, COMP (Compound) – holders vote on protocol changes.
- Exchange tokens: LINK (Chainlink), MKR (Maker) – used for fees, staking, or as collateral.
- Meme coins: SHIB (Shiba Inu) – high‑supply tokens driven by community.
All of these are ERC20 tokens. You can check any token on Etherscan – if it has a contract address and follows the ERC20 interface, it’s ERC20.
How to Store and Manage ERC20 Tokens
Any Ethereum wallet can hold ERC20 tokens. The most popular options:
Important: Never send ERC20 tokens directly to an exchange deposit address that expects a different network (e.g., sending ERC20 USDT to a Binance address that expects BEP‑20 USDT). You can recover them, but it’s a hassle and costs fees.
For a deeper dive, read our best crypto wallets comparison and crypto wallet security guide.
Security Risks and How to Avoid Them
⚠️ Common ERC20 pitfalls
- Approval scams: When you “approve” a malicious contract, it can drain your tokens. Always verify the contract address and use revoke tools like Etherscan or DeFi security best practices.
- Phishing: Fake websites that look like Uniswap or MetaMask. Bookmark real URLs and never enter your seed phrase.
- Low‑liquidity tokens: Scammers create tokens that look legitimate but you can’t sell them because there’s no liquidity. Check DEX screens before buying.
- Gas griefing: Some attacks try to make you spend high gas on worthless transactions. Stick to well‑known dApps.
To stay safe, only interact with verified contracts (check Etherscan’s “verified” badge) and use hardware wallets for large holdings.
Can You Create Your Own ERC20 Token?
Absolutely. Creating an ERC20 token is surprisingly easy, thanks to tools like OpenZeppelin and Remix IDE. You don’t need to be a Solidity expert – you can deploy a standard token contract with just a few clicks.
However, making a successful token is another story. You’ll need a compelling use case, liquidity, community, and often an audit. Many tokens launched on Uniswap end up as “honeypots” or rugged. If you’re serious, read our guide to launching a crypto token.
The Future of ERC20 and Ethereum Upgrades
ERC20 is here to stay – it’s the foundation of the Ethereum economy. But with Ethereum’s transition to proof‑of‑stake and upcoming scalability improvements (like danksharding), the way we interact with ERC20 tokens will evolve:
- Lower fees: Layer 2 rollups and future upgrades will make ERC20 transfers cheaper.
- Account abstraction: Wallets could pay gas in tokens, making UX smoother.
- Cross‑chain standards: Bridges and wrapped tokens (like WETH) will continue to connect ERC20 to other chains.
New standards like ERC20‑G (for gas abstraction) may emerge, but the core ERC20 interface will remain compatible forever – that’s the beauty of Ethereum’s upgrade philosophy.
Frequently Asked Questions
No. ETH is the native currency of Ethereum, not a token. It doesn’t follow the ERC20 standard – it has its own transfer logic and is required for gas fees. Wrapped ETH (WETH) is an ERC20 token that represents ETH 1:1.
No. Bitcoin addresses are on a completely different network. If you send ERC20 tokens to a Bitcoin address, they are lost forever. Always double‑check the receiving network and address format.
It depends on the gas fee you set. If the network is busy and your fee is too low, miners may ignore your transaction. You can speed it up by replacing the transaction with a higher gas price (if your wallet supports it).
ERC20 is on Ethereum; BEP-20 is on Binance Smart Chain. They are functionally identical, but BSC has lower fees and is more centralized. Tokens on one chain cannot be used on the other without a bridge.
You can use Etherscan’s “Token Approval” tool, or platforms like revoke.cash to view and cancel approvals you’ve given to smart contracts. This prevents them from spending your tokens later.
Final Thoughts: ERC20 Is the Backbone of Ethereum
ERC20 tokens power everything from stablecoins to governance, from DeFi lending to NFT marketplaces. Understanding how they work – and how to transfer them safely – is essential for anyone using Ethereum.
As the ecosystem grows, ERC20 will remain the bedrock, evolving with layer 2s and new standards. Whether you’re a trader, a developer, or just curious, you now have the knowledge to navigate the world of ERC20 with confidence.