Gas is the unit that prices the work Ethereum does for you. Every transaction pays gas used multiplied by a price per unit, where the price has two parts: a base fee the network burns, and a tip that goes to the validator who includes you. In 2026 that total is usually a few cents on mainnet.
What is gas on Ethereum, and why does every transaction need it?
Gas is the unit Ethereum uses to measure the work a transaction asks the network to do. Sending ETH is a little work; swapping tokens is more. You pay for that work in ETH, and the gas number is how the network keeps the bill fair, because heavier transactions consume more gas than light ones.
The reason gas exists comes down to how Ethereum runs. Every transaction is executed by thousands of independent computers, called nodes, and each one redoes the same work to check the result. That redundancy is what makes the network trustworthy, but it is not free. Someone has to pay for all that computation, or anyone could clog the whole network for nothing.
Gas is the answer. It puts a price on each step of work, so spam gets expensive fast and honest transactions pay roughly what they cost the network to process. Think of it like a taxi meter: the meter does not care who you are, only how far the EVM has to travel to finish your request. (The EVM, or Ethereum Virtual Machine, is the engine that runs Ethereum's transactions; how it works is covered in our companion guide on how Ethereum works.)
Gas is always paid by the account that sends the transaction. When you send ETH or use an app, the fee comes out of your own wallet in ETH, on top of whatever you are sending. You need a small amount of ETH in your wallet to cover gas, which is why a wallet holding only tokens and no ETH can get stuck: there is nothing to pay the fee with. The token is there, but moving it still costs gas in ETH.
One thing to keep straight from the start: gas is quoted as a number of units and a price per unit, but you always pay the final bill in ETH. The rest of this guide unpacks those two pieces and shows what they add up to in real money.
Gwei, gas units, and gas price: how the numbers fit together
Three numbers decide your fee: how many gas units your transaction uses, the price per unit, and the price of ETH. Gas units measure the work, and the price per unit is quoted in gwei, a tiny slice of ETH. Multiply units by price for the fee in ETH, then by the ETH price for the cost in dollars.
Start with gwei, because the word trips up almost every beginner. One gwei is one-billionth of an ETH (0.000000001 ETH). Gas prices are quoted in gwei simply because the numbers would be unreadable otherwise. Saying "the gas price is 5 gwei" is far easier than writing it out in ETH with nine zeros after the decimal point.
Next comes the fee formula, and it is genuinely simple:
Total fee = gas units used × (base fee + priority fee)
The gas units depend on what you are doing, and the network largely sets them for you. The base fee and priority fee are the price per unit, both quoted in gwei (source: Ethereum gas and fees).
Here is a quick worked example using calm 2026 conditions. A plain ETH transfer uses 21,000 gas units. Suppose the base fee is 0.15 gwei and you add a 0.05 gwei tip, for 0.2 gwei total. Then the fee is 21,000 × 0.2 = 4,200 gwei, which is 0.0000042 ETH. With ETH near 1,900 dollars, that is under one cent. The same maths works on a busy day: if the price climbs to 5 gwei, the fee becomes 21,000 × 5 = 105,000 gwei, or about 0.20 dollars. The formula never changes; only the price per unit moves.
If you want to see how these pieces feed a full fee estimate inside a wallet, that step-by-step calculation lives in our guide to calculating Ethereum transaction fees.
How the EVM meters gas: why some operations cost more
The EVM charges a fixed amount of gas for each individual operation it performs, and the amounts are not equal. Cheap operations like simple arithmetic cost a few gas units. Expensive operations like writing data that every node must store forever cost thousands. The total gas a transaction uses is just the sum of every operation it triggers.
Ethereum's code is built from small instructions called opcodes, and each opcode has a price set by the protocol. The prices reflect the real cost to the network. Doing a calculation is quick and cheap. Saving a new piece of data to the blockchain is slow and permanent, because every node has to keep that data more or less forever, so it costs far more.
A few representative costs make the pattern clear:
Operation (opcode) | What it does | Gas cost |
|---|---|---|
ADD | Add two numbers | 3 |
SUB | Subtract two numbers | 3 |
SLOAD | Read a value from contract storage | 100+ (more if first access) |
SSTORE | Write a new value to contract storage | up to 20,000 |
The gap between adding numbers and saving data, roughly three gas versus twenty thousand, is why a simple payment is cheap and a complex smart-contract action is not (source: Ethereum Yellow Paper). It is also why two common transactions have very different baselines. A plain ETH transfer uses 21,000 gas units, the protocol floor for moving ETH from one account to another. Sending a token like USDT uses roughly 65,000 gas, because the network has to run the token contract's code and update its stored balances on top of the basic transfer.
There is a small wrinkle worth knowing. The first time a transaction touches a particular piece of storage, it pays a higher "cold" price; touching the same data again in the same transaction is cheaper, a "warm" access (source: EIP-2929 specification). This is why an action that reads the same value several times is not as costly as it might first appear, and why developers work hard to keep storage use low. As a user you never set any of this by hand; the network adds it all up for you.
You do not need to memorise opcode prices. The point to carry forward is simple: the more storage and computation your transaction touches, the more gas units it uses, and the bigger the fee.
Base fee, priority fee, and EIP-1559: the two-part fee
Since August 2021, every Ethereum fee has had two parts. The base fee is set automatically by the network and is burned, not paid to anyone. The priority fee is an optional tip you add on top, and it goes to the validator who includes your transaction. The change that introduced this split is called EIP-1559.
The base fee is the clever part. The network sets it automatically based on how full recent blocks have been, and it adjusts every block by at most 12.5 percent. When blocks are more than half full, demand is high, so the base fee rises. When blocks are less than half full, it falls. Because the change is capped at 12.5 percent per block, the price moves smoothly instead of spiking unpredictably, which is why wallets can estimate your fee reliably (source: EIP-1559 specification).
What surprises newcomers is that the base fee is burned. The ETH you pay as a base fee is permanently removed from circulation, not handed to a validator. The deeper effect this burn has on ETH's supply is its own topic, covered in our piece on ETH and the burn. For fee purposes, the takeaway is that only the tip actually pays someone.
The priority fee, or tip, is how you ask to be processed sooner. Validators choose which transactions to include, and a larger tip makes yours more attractive. On a quiet network a tiny tip is plenty. When the network is busy, raising the tip is the lever that gets you in faster.
You will also see a setting called max fee per gas in your wallet. This is the ceiling you are willing to pay per unit, covering the base fee plus your tip. If the base fee ends up lower than your ceiling, you are only charged what the network actually required and the difference is refunded. The full history and finer mechanics of EIP-1559 are covered in our EIP-1559 deep dive; for this guide, the two-part fee is all you need.
What a typical Ethereum transaction costs in 2026
In 2026, a normal mainnet transaction usually costs a few cents, not the dollars it cost in earlier years. Gas prices spent much of the year below one gwei, because most everyday activity has moved to Layer 2 networks, leaving Ethereum's main chain far less congested.
As of June 3, 2026, the mainnet gas price sat near 0.15 gwei (source: Etherscan gas tracker). That is a big shift from the Ethereum many guides still describe, where a token swap could cost 20 or 50 dollars at peak. Those numbers came from a period when everything competed for space on mainnet. Today most of that activity runs on Layer 2 rollups, which settle back to Ethereum at a fraction of the cost (source: Ethereum Layer 2 overview), and mainnet itself is usually cheap. Why Layer 2s exist and how their fees compare is covered in our guide on Layer 2 fees versus mainnet, and the broader question of how Ethereum and Bitcoin differ is covered in Bitcoin versus Ethereum.
Here is roughly what common transactions cost on mainnet in 2026, with ETH near 1,900 dollars. The figures are illustrative and move with the gas price, so treat them as a guide, not a quote:
Transaction | Gas units (approx.) | Calm day (~0.2 gwei) | Busier day (~5 gwei) |
|---|---|---|---|
Send ETH | 21,000 | under $0.01 | about $0.20 |
Send a token (USDT) | ~65,000 | about $0.03 | about $0.62 |
Swap on a DEX (Uniswap) | ~150,000 | about $0.06 | about $1.43 |
The gas units barely change from day to day, because they depend on the work, not the market. What moves your fee is the price per gas, which rises and falls with how busy the network is. This is the same reason exchanges keep adjusting their withdrawal fees, and it is worth seeing how those fees compare to the broader cost of using crypto in our overview of crypto fees for investors.
From Blofin's operational perspective, when our hot-wallet account signs a user's withdrawal, that transaction enters the same public queue as any retail swap. We pay the same base fee, we add a tip the same way, and we wait in the same line ordered by fee. Being an exchange does not move our transaction up the queue; only the size of the tip does. The fee market is fee-blind, not actor-blind, which is why our withdrawal fees track live gas conditions rather than any special rate.
Gas limits: the per-transaction and per-block ceilings
There are two gas limits, and they do different jobs. Your transaction has a gas limit, which is the most gas you authorise it to use. The network has a block gas limit, which caps the total gas all transactions in one block can use together. The first protects you; the second protects the network.
Your transaction's gas limit is a safety ceiling. For a plain ETH transfer, 21,000 is both the cost and the sensible limit. For a smart-contract action, your wallet estimates a higher limit to leave room for the work. If a transaction uses less gas than its limit, you are only charged for what it actually used, and the unused gas is never spent (source: Ethereum transactions documentation). Setting a limit a little above the estimate is normal; setting it too low is risky, as the next section explains.
A quick example shows why the limit is a ceiling and not the price. Say you set a gas limit of 50,000 for an ETH transfer that only needs 21,000. The transaction still uses 21,000, you pay for 21,000, and the other 29,000 is handed back unused. The limit only mattered as a cap on the worst case. The danger runs the other way: set the limit below what the work needs, and the transaction can run out of gas partway through, which is the failure that still costs you.
The block gas limit is a network-wide cap. In 2026 it sits around 60 million gas units, raised in steps from the 30 million that held for years, which lets each block hold more transactions (source: Etherscan block stats). Blocks aim to run about half full on average, and that target is exactly what the base fee uses to decide whether to rise or fall. When a block runs above the target, the base fee ticks up; below it, the base fee eases off.
Why a failed transaction still costs gas
A transaction that fails can still cost you gas, and the reason is fair once you see it. If the network did real work before discovering the transaction could not finish, that work has to be paid for. The validators and nodes already spent the effort, so the gas they consumed is charged even though the result was thrown away.
It helps to separate two different failure modes, because only one of them costs you:
The first mode is a transaction that is rejected before it ever runs. If you set a gas limit below the minimum a transaction needs, the network refuses it during validation and it never enters a block. Nothing ran, so nothing is charged. This is the harmless case.
The second mode is a transaction that starts running and then fails partway through, often because it hit its gas limit or the contract deliberately reverted. Here the EVM did real work first: it ran the contract's code, changed some values, and only then discovered it could not complete. At that point the changes are rolled back to keep the state clean, but the gas already burned is gone. You pay for the work, and you get nothing in return. This is the case that stings.
From Blofin's operational perspective, the rare withdrawal where one of our broadcasts runs out of gas mid-execution behaves exactly this way. The transaction reverts, the user receives nothing on that attempt, and the gas consumed before the revert is charged to our hot-wallet account, the same as it would be for any user. We watch for this failure category as part of our withdrawal-pipeline health checks, because it signals a limit that was estimated too tightly. The lesson for any user is the same one we apply: let your wallet set the gas limit rather than forcing it down to save a fraction of a cent.
Frequently asked questions
What is the difference between gwei and ETH?
They are the same currency at different scales. One gwei is one-billionth of an ETH (0.000000001 ETH). Gas prices are quoted in gwei because the numbers are small and would be hard to read in full ETH. You still pay the final fee in ETH; gwei is just a convenient unit for the price per gas, the way cents are a convenient unit for fractions of a dollar.
Why does Ethereum charge gas at all?
Because every transaction is run and checked by thousands of independent computers, and that work is not free. Gas puts a price on each step of computation, so heavy transactions pay more than light ones and nobody can flood the network with free spam. Without a cost per operation, a single bad actor could run endless loops and stall the whole network. Gas turns computing power into something that has to be paid for.
Why did my failed transaction still cost gas?
Because the network did real work before the transaction failed. If it started running and then reverted partway through, the computation up to that point was already performed by every node, so the gas it used is charged even though the change was undone. The exception is a transaction rejected before it runs at all, for example one with a gas limit set below the minimum; that one is refused during validation and costs nothing.
Where does the base fee go?
It is burned, meaning it is permanently destroyed and removed from circulation. The base fee is not paid to validators. Only the priority fee, the tip, goes to the validator who includes your transaction. This burn was introduced by EIP-1559 in 2021 and steadily removes ETH from the total supply whenever the network is in use.
Can I set my gas fee to zero?
Not in practice. The base fee is set by the network and you cannot pay less than it, so a transaction offering zero will not be valid. You can set the priority tip to zero when the network is quiet, and it may still be included, but it will be lower priority. On a busy network, a zero tip can leave your transaction waiting a long time or never included at all. Bitcoin handles fees differently, with no burned base fee and a market driven by block space rather than a protocol-set price; our guides on why Bitcoin fees can run high and how to choose Bitcoin fees cover that contrast.
Researched and written by the Blofin Academy editorial team with AI-assisted drafting. Primary sources include the Ethereum gas and fees documentation, the EIP-1559 specification, and the Etherscan gas tracker for live 2026 figures. All facts independently verified against cited documentation current as of June 2026.
This article is for informational purposes only and does not constitute financial advice, investment guidance, or a recommendation to buy, sell, or hold any digital asset. Cryptocurrency markets involve significant risk and you should conduct your own research and consult qualified professionals before making decisions. Blofin Academy content reflects the state of public information at time of publication; gas prices, fees, and network conditions change frequently.