If you have ever tried to send crypto or use a decentralised app and been surprised by an unexpected fee — that is a gas fee. For many beginners, gas fees are confusing and sometimes alarming. Why are they sometimes €0.01 and sometimes €50? Why do you need ETH to send an ETH token? Why does the fee change every few minutes?
This guide explains gas fees from the ground up in plain English — what they are, why they exist, why they vary so much, and how to pay as little as possible.
📋 What's covered in this guide
What Are Gas Fees?
Gas fees are the transaction fees you pay whenever you interact with a blockchain. They are called gas fees because the original analogy comes from Ethereum — just like a car needs petrol to run, a blockchain transaction needs gas to execute.
Every time you do any of the following, you pay a gas fee:
- Send crypto from your wallet to another address
- Withdraw crypto from an exchange to your own wallet
- Swap tokens on a DEX like Uniswap or PancakeSwap
- Interact with a smart contract or DeFi protocol
- Mint or transfer an NFT
Gas fees are not paid to an exchange or to any company. They go directly to the validators or miners who process and confirm your transaction on the blockchain. Think of them as a tip to the people keeping the network running — without fees, there would be no incentive for anyone to process transactions.
Simple version: Gas fees are the cost of using the blockchain. They pay the people who run the network to process your transaction. Every blockchain has them, though the amounts vary enormously between networks.
Why Do Gas Fees Exist?
Blockchains are decentralised networks — thousands of computers around the world that all work together to record and verify transactions. These computers are run by real people who invest in hardware and electricity. Gas fees are how those people get paid.
Gas fees also serve a second purpose: they prevent spam. If transactions were free, anyone could flood the network with millions of worthless transactions and bring it to a halt. By charging a fee for every transaction, the network naturally filters out low-value activity.
This is fundamentally different from a centralised exchange like Coinbase, where the company manages its own internal database and can process trades for free internally, charging you a trading fee as their business revenue instead.
Why Do Gas Fees Vary So Much?
This is the part that confuses most beginners. Gas fees can be €0.01 at 3am on a Tuesday and €40 on a busy Friday afternoon — on the same network, for the same type of transaction. Here is why.
Each blockchain processes transactions in batches called blocks. Each block has a limited amount of space. When more people want to transact than there is space available, they effectively bid against each other — whoever is willing to pay more gets their transaction included in the next block first.
When the network is quiet, there is plenty of space and fees are low. When the network is busy — during a popular NFT mint, a market crash, or a major news event — everyone wants their transaction processed immediately and fees skyrocket as people outbid each other.
On Ethereum specifically, gas fees are measured in Gwei (a tiny fraction of ETH). The fee you pay is calculated as: Gas units × Gas price. A simple ETH transfer uses a fixed amount of gas units (21,000), while complex smart contract interactions use significantly more.
Real example: Sending ETH from one wallet to another might cost €0.50 when the network is quiet. Swapping tokens on Uniswap during a busy period might cost €30–€80 because it is a more complex operation and the network is congested. This is not unusual — it is simply how Ethereum works at peak times.
Why Do You Need ETH to Send ETH Tokens?
This catches many beginners completely off guard. You have USDT in your Ethereum wallet and want to send it somewhere — but the transaction fails because you do not have enough ETH. Why do you need ETH to send USDT?
The answer is that gas fees on the Ethereum network are always paid in ETH — the native currency of that blockchain. It does not matter what token you are sending. Whether it is USDT, USDC, DAI, or any other ERC-20 token, the gas fee to process that transaction on the Ethereum blockchain is always paid in ETH.
The same rule applies on every blockchain. On BNB Chain, gas fees are paid in BNB. On Solana, they are paid in SOL. On Polygon, they are paid in MATIC (now POL). The native coin of each blockchain is always the currency used to pay that network's gas fees.
Beginner trap: If you are using MetaMask or any self-custody wallet, always keep a small amount of the network's native coin available for gas fees. If you run out of ETH on Ethereum, you cannot send any tokens at all — even if your wallet shows a positive token balance. Keep at least €5–10 worth of the native coin on any network you use regularly.
Gas Fees by Network
Not all blockchains are created equal when it comes to gas fees. Here is how the major networks compare:
| Network | Native coin for gas | Typical simple transfer fee | Typical swap fee |
|---|---|---|---|
| Ethereum | ETH | €0.50 – €30+ | €5 – €80+ |
| BNB Chain | BNB | €0.05 – €0.30 | €0.10 – €0.50 |
| Solana | SOL | €0.001 – €0.01 | €0.01 – €0.05 |
| Polygon | POL | €0.001 – €0.05 | €0.01 – €0.10 |
| Arbitrum (L2) | ETH | €0.01 – €0.20 | €0.05 – €0.50 |
| Base (L2) | ETH | €0.01 – €0.15 | €0.05 – €0.30 |
| Avalanche | AVAX | €0.05 – €0.50 | €0.10 – €1.00 |
Fees fluctuate constantly — the figures above are typical ranges during normal network conditions. Ethereum fees in particular can be multiples higher during periods of heavy congestion.
How to Pay Less in Gas Fees
Gas fees are unavoidable on the blockchain, but there are practical ways to significantly reduce what you pay:
⏰ Time your transactions
Ethereum gas fees are significantly cheaper late at night and in the early hours of the morning — typically between midnight and 8am European time — when network activity is lowest. If your transaction is not urgent, wait for a quiet period. Websites like ethgasstation.info and ultrasound.money show real-time and historical gas prices to help you pick the right moment.
🌐 Use a cheaper network
If you are regularly using DeFi or DEXs, consider switching from Ethereum mainnet to a Layer 2 like Arbitrum or Base, or an alternative blockchain like Solana or BNB Chain. The same actions cost a fraction of the price on these networks. Most major DeFi protocols now exist on multiple networks.
📦 Batch your transactions
If you need to make multiple transactions, try to do them in the same low-fee window rather than spreading them across multiple expensive peak periods. Each transaction costs gas separately, so timing them together saves money.
🏦 Use a centralised exchange for large transfers
If you are simply moving large amounts of crypto between wallets or converting between coins, doing it on a centralised exchange like Coinbase or Kraken and withdrawing the result may work out cheaper than paying high Ethereum gas fees — especially if you are converting tokens rather than just transferring them.
⚙️ Adjust your gas settings
Most wallets let you manually set your gas fee. If the transaction is not time-sensitive, set it slightly below the current recommended fee. Your transaction may take a bit longer to confirm but you will pay less. Most wallets show a "slow", "standard", and "fast" option — slow is fine for non-urgent transactions.
What Happens if Your Transaction Gets Stuck?
If you set your gas fee too low, your transaction may end up stuck in a pending state — submitted to the network but not yet included in a block because other transactions with higher fees keep jumping the queue.
Your funds are not lost. The transaction is simply waiting. You have two options:
- Wait it out. If network congestion drops to your fee level, the transaction will eventually go through. This can take minutes, hours, or occasionally longer during very busy periods.
- Speed it up or cancel it. Most wallets — including MetaMask — let you speed up a pending transaction by resubmitting it with a higher fee, or cancel it entirely by sending a replacement transaction with the same nonce and a higher fee. The replacement transaction overwrites the pending one.
Good to know: A stuck transaction cannot harm your wallet or lock your funds permanently. The worst case is that it stays pending for a while and then gets dropped by the network, returning your funds to your wallet automatically.
Want to understand networks in more depth?
Our blockchain guides explain how each major network works and what it is best used for.