Getting Started

What are gas fees?

Last updated: 10/02/2025

Introduction

If you’ve ever transferred cryptocurrency or interacted with a decentralized application (DApp) on networks such as Ethereum or KCC Chain, you’ve probably noticed something called gas fees. These fees are a core part of blockchain operations, functioning as the “fuel” that powers and secures the network.
The concept of gas fees was first introduced by Ethereum, and the term “gas” is now commonly associated with Ethereum transactions and smart contracts. In this article, we’ll focus mainly on Ethereum’s gas system, though many other blockchains also use the term to describe their own transaction costs.

What Are Gas Fees?

Gas fees are the costs you pay to perform actions on a blockchain. Every time you send or receive cryptocurrencies like ETH or KCS, the transaction requires computation to be validated and permanently recorded on the blockchain.
Put simply, gas is the unit that measures the computational effort behind a transaction—whether it’s a basic ETH transfer or a complex smart contract interaction. You can think of gas as the energy that keeps the Ethereum network running.
 
Blockchain
Chain Name
Gas Token (Used to Pay Transaction Fees)
Ethereum
Ethereum Mainnet
$ETH
BNB Chain
BNB Smart Chain (BSC)
$BNB (BNB Chain)
Polygon
Polygon PoS
$POL (Polygon Chain)
Arbitrum
Arbitrum One
$ETH (Arbitrum Chain)
Optimism
Optimism
$ETH (Optimism Chain)
Avalanche
Avalanche C-Chain
$AVAX (Avalanche Chain)
Base
Base
$ETH (Base Chain)
Solana
Solana Mainnet
$SOL 
Tron
Tron Mainnet
$TRX 
Bitcoin
Bitcoin Mainnet
$BTC (No smart contract support)
KCC
KuCoin Community Chain (KCC)
$KCS 

How Do Gas Fees Work?

When you send a transaction or execute a contract, the Ethereum network breaks it into small computational steps. Each of these steps consumes gas. The more complex the task, the more gas it requires.
Gas fees are paid in gwei, a tiny fraction of ETH (1 ETH = 1 billion gwei). By paying these fees, you motivate validators to prioritize your transaction and include it in the blockchain.

Why Do Gas Fees Change?

Gas costs vary due to two main factors: network congestion and transaction complexity.
  • Network congestion: Ethereum is a shared, decentralized system with millions of users. When demand is high—such as during popular NFT drops or DApp launches—users compete for validator attention by offering higher gas fees. This bidding process pushes fees upward.
  • Low activity periods: When the network is quiet, competition drops and fees become cheaper.
  • Complexity of transactions: Even when traffic is low, complicated transactions (e.g., multi-step smart contracts) consume more gas than simple transfers, making them costlier.
This flexible pricing ensures resources are allocated efficiently but can make fees unpredictable during peak times.

Why Gas Fees Matter

Although they can sometimes feel like an obstacle, gas fees play essential roles in keeping Ethereum functional and secure:
  • Security: By attaching costs to every action, gas fees deter spam and malicious activity.
  • Incentives: Validators earn gas fees as rewards, encouraging them to process and secure transactions.
  • Efficiency: Developers are motivated to write optimized smart contracts to avoid unnecessary costs.
  • Prioritization: Users can pay more to ensure faster confirmations when the network is congested.

Tips for Managing Gas Fees

Understanding how gas works can help you save money and plan transactions better. Here are some practical strategies:
  • Choose wallets or apps that provide real-time estimates of gas fees, so you know what to expect before sending a transaction. You can also use blockchain explorers like Etherscan or KccScan to check gas prices in real time.
  • If you’re not in a rush, set a lower gas price—just note that it may take longer to process.
  • Expect higher fees for complex interactions (like DeFi or NFT transactions).
  • Transact during off-peak hours, when traffic is lighter and fees are lower.
  • Keep track of Ethereum upgrades and Layer 2 solutions, which aim to reduce fees and speed up confirmations.

FAQ

1. Why do I need to pay gas fees?
i. To reward miners or validators for processing your transaction
ii. To prevent spam or malicious transactions (such as network-level junk mail)
iii. To help keep the blockchain running smoothly and securely

2. What can I do with a Web3 wallet?
You can send, swap, stake, withdraw, and perform any transaction that requires interaction with the blockchain.

3. Why am I seeing an “Insufficient Gas Fee” message?
You’ll see this warning if your gas token balance is too low to cover the gas fees — or if you don’t have any gas tokens at all.

4. What should I do if I don’t have enough gas fees?
You may choose to acquire the necessary tokens by using the Receive, Swap, or Withdraw from Exchange functions.