Blockchain technology powers a growing ecosystem of decentralized applications, from sending crypto to friends to engaging with DeFi platforms and Web3 games. Every action you take on these networks—whether it's transferring tokens or interacting with a smart contract—requires a small fee known as a network fee or gas fee. This guide breaks down how network fees work across Ethereum and Layer 2 (L2) blockchains, which tokens you need to pay them, and how to ensure your transactions go smoothly.
👉 Discover how to manage your crypto transactions with confidence and ease.
What Are Network Fees?
A network fee is a payment made to blockchain validators or miners to process and confirm your transaction. This fee is not collected by wallet providers like Zengo—it goes directly to the network’s infrastructure operators. The cost fluctuates based on network demand:
- During periods of high congestion (e.g., during NFT mints or major market moves), fees rise.
- When traffic is low, fees drop significantly.
Each blockchain uses its own native token for fee payments. For example:
- Ethereum (mainnet): ETH
- Polygon: MATIC
- Arbitrum One: ETH (on Arbitrum)
- Optimism: ETH (on Optimism)
Always ensure you have enough of the correct token in your wallet to cover the gas fee—otherwise, your transaction will fail.
Ethereum and ERC-20 Tokens: The Foundation
Many popular digital assets—including stablecoins like USDC and USDT, utility tokens like Chainlink (LINK), and memecoins like Shiba Inu (SHIB)—are built as ERC-20 tokens on the Ethereum blockchain. These tokens rely on Ethereum’s infrastructure for transfers and smart contract interactions.
However, due to Ethereum’s scalability limitations, high gas fees can make small transactions costly. That’s where Layer 2 (L2) solutions come in.
What Is Layer 2?
Layer 2 networks are secondary protocols built on top of Ethereum (Layer 1) that process transactions off-chain and later settle them on the main Ethereum blockchain. This reduces congestion and slashes fees while maintaining security.
Popular Ethereum L2s include:
- Arbitrum One
- Optimism
- Base
These networks still use ETH as their native gas token—but it's ETH specific to that L2 network, not standard Ethereum from the mainnet.
⚠️ Important: Sending ETH from one network (e.g., mainnet) directly to an L2 wallet address without using a bridge will result in permanent loss of funds.
How to Pay Gas Fees on Different Networks
To successfully execute any transaction, you must pay the network fee using the correct native token for that chain.
Here are real-world examples:
- Sending USDT on Arbitrum One? You’ll need ETH deposited on Arbitrum One to cover the gas fee.
- Using a DeFi app on Polygon? MATIC is required for transaction validation.
- Minting an NFT on Optimism? You’ll need ETH bridged to the Optimism network.
👉 Learn how to securely handle multi-chain transactions across Ethereum and L2s.
How to Get Network Fee Tokens in Your Wallet
You can’t transact without gas—but acquiring the right tokens is simple. Here are three reliable ways to get started:
1. Buy Directly Through Your Wallet
Many wallets, including Zengo, integrate with third-party providers like Transak to let you purchase crypto instantly. You can buy ETH, MATIC, or even L2-specific ETH directly from your mobile app starting at just $5.
2. Swap Existing Crypto
Already hold Bitcoin or another cryptocurrency? Use your wallet’s built-in swap feature to exchange it for the gas token you need. For instance, swap BTC for ETH if you're preparing to interact with an Ethereum-based dApp.
3. Receive From Another Wallet or Exchange
Transfer the required gas token from another wallet or exchange account. Just make sure:
- You’re sending to the correct network (e.g., withdraw MATIC via Polygon, not BSC).
- You leave enough balance in the source wallet to cover withdrawal fees.
🔍 Pro Tip: Always double-check network compatibility before sending funds. A mismatch between sending and receiving networks is one of the most common causes of irreversible fund loss.
How Much Gas Will My Transaction Cost?
When initiating a transfer or signing a Web3 action in your wallet, the estimated network fee appears on the confirmation screen—before final approval. This gives you full visibility so you can decide whether to proceed.
If you want to estimate costs ahead of time:
- For Ethereum mainnet: Use tools like Etherscan Gas Tracker to monitor real-time rates.
- For L2s: Most have lower and more predictable fees. Arbitrum and Optimism typically charge only a few cents per transaction.
For standard ERC-20 token transfers (like USDC or USDT), a gas limit of 21,000 units is typical. Complex smart contract interactions may require up to 45,000 or more.
Frequently Asked Questions
Q: Can I use USDC to pay gas fees on Ethereum?
A: No. Only the native token—ETH—can be used to pay gas fees on Ethereum and its L2s.
Q: Why do I need ETH on Arbitrum if I’m just sending USDC?
A: Because USDC on Arbitrum exists within that network’s ecosystem. All transactions there require ETH (on Arbitrum) as gas, even if you're moving non-native tokens.
Q: What happens if I don’t have enough gas token?
A: Your transaction will fail and may still consume part of your balance as a “failed transaction” fee.
Q: Can I send ETH from Ethereum mainnet directly to Arbitrum?
A: Not directly. You must use a cross-chain bridge to move ETH from Layer 1 to Layer 2 safely.
Q: Are L2 fees cheaper than Ethereum mainnet?
A: Yes—significantly. While mainnet fees can spike to $10+ during peak times, L2s often cost less than $0.10 per transaction.
Q: How do I know which network my tokens are on?
A: Check your wallet interface—it should display the network name (e.g., “Ethereum,” “Polygon,” “Arbitrum”). If unsure, consult support before acting.
👉 Stay ahead with tools that simplify multi-network crypto management.
Final Tips for Smooth Transactions
- Always verify the network before sending or swapping.
- Keep a small reserve of native gas tokens (ETH, MATIC, etc.) in each wallet where you hold assets.
- Use trusted bridges when moving assets between chains.
- Enable price estimation features in your wallet to avoid surprises.
Understanding how network fees work empowers you to navigate the crypto world safely and efficiently. Whether you're new to Web3 or expanding into L2 ecosystems, knowing what fuels your transactions ensures every move counts—without costly mistakes.
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