Gas Fees

A gas fee is what a blockchain network charges for executing a transaction or running contract code. The SEC and CFTC's March 2026 interpretation describes the general arrangement: a functional crypto system may require users to pay transaction, or gas, fees in the system's native digital commodity, and those fees, alongside newly generated units, typically serve as an incentive mechanism rewarding participation in and use of the system. The term is most associated with Ethereum, whose developer documentation defines gas as the unit measuring the computational effort required to execute specific operations on the network, but the concept is general: a network that lets anyone submit work needs a price on that work, or nothing stops the network being flooded.

The fee is not a percentage of what is being moved. It is a price on computation, so sending $50 and sending $50,000 by the same method cost the same, while a complicated contract interaction costs several times more than either. That is the single most counterintuitive property of the charge and the source of most of the surprises around it.

Two numbers determine what a transaction costs, and they are set by different parties. The amount of gas consumed is determined by the work the transaction does: a plain transfer consumes a fixed amount, and a contract call consumes more depending on what the code does. The price per unit of gas is determined by demand for space in the next block. Ethereum's documentation quotes gas prices in gwei, a denomination equal to one-billionth of an ether, because the numbers are otherwise unreadable.

Since 2021 the price per unit on Ethereum has had two components, and the split matters because they go to different places. An exchange filing published in the Federal Register describes the change: the EIP-1559 upgrade altered the methodology used to calculate the fees paid to miners, now validators, and splits the fee into a base cost and a priority fee, with the base cost removed from circulation, or burnt, and the priority fee paid to the validator. The same filing notes the consequence for supply: new issuance can be partially or completely offset by that burn, at a rate that varies with network usage, and the supply has occasionally been reduced over a 24-hour period as a result. So a portion of what a user pays in fees is not revenue to anyone; it is destroyed. The base cost is set by the protocol from how full recent blocks have been, and the priority fee is the part a user can raise to be included sooner.

Gas limit and gas price are separate controls and are commonly confused. The limit is the maximum amount of gas the sender is willing to consume, and Ethereum's documentation states that gas not used is returned rather than charged, so setting a generous limit does not overpay. There is a companion ceiling on the price per unit, which the documentation calls the maximum fee per gas: for a transaction to execute, that maximum must exceed the base cost plus the tip, and the sender is refunded the difference. Most wallets set both automatically, which is why a user typically sees one estimated total rather than three parameters.

The failure cases are worth stating precisely, because the common shorthand gets one of them wrong. Ethereum's documentation distinguishes two situations. If the gas limit is set below what the transaction needs even to begin, the transaction fails during validation, is rejected before being included in a block, and no gas is consumed. If the transaction begins and then runs out of gas partway through, for example because a contract call uses up the allowance, the network reverts every change the transaction made but all the gas provided is still consumed for the work performed. The blunt claim that a failed transaction always costs gas is therefore half right, and the half that is right is the expensive half: a transaction that fails on chain is paid for and achieves nothing.

For a household holding a small position, the fee is a real input to a decision rather than a technicality. Moving crypto off a platform into a wallet you control is a network transaction, so it carries a fee, and that fee is the same whether the balance being moved is large or small. A position small enough that the fee is a meaningful percentage of it is a position that is awkward to self-custody, awkward to consolidate later, and awkward to move again. Whether a network fee adds to basis or is otherwise deductible is a tax question and is not answered here.

A wallet estimates two things before it submits a transaction: how much gas the operation will consume, and what price per unit is currently needed for inclusion. The user approves, the transaction is broadcast, and if it is included in a block the fee is deducted from the sender's balance in the network's own asset. The formula Ethereum's documentation gives is the amount of gas used multiplied by the sum of the base fee and the priority fee.

A hypothetical, with round numbers chosen to be checkable rather than current. Bea interacts with a contract, and her wallet sets a gas limit of 120,000 units because the operation is more involved than a plain transfer. The base cost at that moment is 14 gwei per unit and her wallet adds a priority fee of 2 gwei, so the price per unit is 16 gwei.

The transaction turns out to consume 95,000 units rather than the full 120,000. She is charged 95,000 multiplied by 16, which is 1,520,000 gwei, or 0.00152 ether. The remaining 25,000 units of the limit are not charged. Of what she paid, the base portion is 95,000 multiplied by 14, or 1,330,000 gwei, and that is destroyed; the validator receives 95,000 multiplied by 2, or 190,000 gwei. If ether is trading at a hypothetical $2,500, her total fee is about $3.80.

Now the two things that make the number matter. If Bea was moving $6,000 of assets, $3.80 is about six hundredths of one percent and is not worth thinking about. If she was moving $60, the same $3.80 is roughly 6 percent, and doing it twice would cost more than a tenth of the position.

And if her wallet had set the limit at 60,000 instead, the contract would have run out of gas partway through. Every change would be undone, and she would still be charged 60,000 multiplied by 16, or 960,000 gwei, about $2.40 at the same hypothetical price, for a transaction that accomplished nothing.

Why the charge exists and what it does well

• It prices scarce block space, so the network cannot be flooded with junk work at no cost, and it prevents code from running indefinitely.
• It pays the participants who validate transactions, which is part of what keeps the network running.
• It is transparent and computable in advance. The amount of gas an operation needs and the current price per unit are both public before you commit.
• Charging for computation rather than for value means a large transfer is not penalized relative to a small one.

What it costs a user

• The fee is unrelated to the size of the transaction, so small positions bear a disproportionate cost and can become uneconomic to move at all.
• It is unpredictable in advance over any horizon longer than minutes, because the price per unit tracks demand for block space.
• It must be paid in the network's own asset, so holding a token means also holding a balance of a second asset purely to be able to act.
• A transaction that reverts on chain still consumes the gas it used, so a failure can be paid for in full.