A gas fee is what you pay a blockchain network to process your transaction. On Ethereum, "gas" is the unit that measures how much computing work an operation needs. Your fee is the gas your transaction uses multiplied by the price per unit of gas. That price has two parts: a base fee set by the protocol, which is burned, and an optional tip (the priority fee), which goes to the validator. You pay the fee whether the transaction succeeds or fails.
The latest change: October 2026
On 22 October 2026 the Ethereum Foundation postponed Glamsterdam, the next network upgrade, on the Hoodi testnet. Activation there had been set for 26 October 2026. Core developers chose to delay it on the ACDE #248 call so they could look further at how EIP-8037 interacts with smart contracts already on mainnet. No new testnet date has been set, and the Foundation's post does not set a mainnet date. It says mainnet users and ETH holders do not need to do anything.
Glamsterdam matters here because it changes gas pricing. The Foundation's 16 October 2026 announcement lists, among others:
- EIP-8037, which "increases and separately meters the cost of creating state"
- EIP-8038, which "updates state-access costs"
- EIP-7976 (Increase Calldata Floor Cost) and EIP-7981 (Increase Access List Cost)
- EIP-7778 (Block Gas Accounting without Refunds)
- EIP-8261 (Gas Limit Schedule), the mechanism that was to raise Hoodi's gas limit to 200 million at activation; that increase was postponed as well
None of this applies to mainnet yet. Until a mainnet date is announced, the fee rules described below remain in force.
How an Ethereum gas fee is calculated
The units
- Gas measures the computing work an operation needs. A standard ETH transfer needs a gas limit of 21,000 units. Smart contract calls use more, and the amount depends on what the contract does.
- Gwei is the unit fees are quoted in. One gwei is one-billionth of an ETH (0.000000001 ETH).
The three numbers you set or see
Since EIP-1559, which went live in the London upgrade in August 2021, every transaction has:
- Base fee. The protocol sets it from how full the previous block was, and it is burned. Each block targets half of the block gas limit. If the parent block used more gas than the target, the base fee rises; if it used less, the base fee falls. It can change by at most 12.5% per block (the spec's change denominator is 8).
- Priority fee (tip). This is paid to the validator who includes your transaction. The protocol fills the base fee first, so the tip is capped at whatever your maximum fee leaves over.
- Max fee per gas. This is the most you will pay per unit of gas. You are refunded the difference between the max fee and the base fee plus tip.
You also set a gas limit, the maximum gas the transaction may use. Gas you don't use is refunded.
Effective price per gas = base fee + tip (with the tip capped by your max fee) Fee = gas used × effective price per gas
A worked example (illustrative figures)
Say you send ETH, which uses 21,000 gas, when the base fee is 30 gwei and you tip 2 gwei:
21,000 × (30 + 2) gwei = 672,000 gwei = 0.000672 ETH
Of that, 630,000 gwei (the base fee part) is burned and 42,000 gwei goes to the validator. The gwei values are examples only; real base fees change every block.
Why fees exist at all
Ethereum's documentation gives two reasons. A charge on every computation stops attackers from spamming the network. Gas limits also guard against "accidental or hostile infinite loops or other computational wastage in code."
Why you pay for a failed transaction
Ethereum's documentation states: "The fee is paid regardless of whether a transaction succeeds or fails." The network did the work up to the point where your transaction stopped. A common cause is a gas limit set too low: the transaction runs out of gas partway through, reverts, and is still charged. For contract calls, the safer default is the gas limit your wallet estimates, unless you know the transaction's gas profile.
What will this transaction cost in ETH?
Enter the gas your transaction uses, the base fee, your tip and your max fee per gas to see the fee in ETH.
| Gas your transaction uses | Base fee (burned) | Priority fee (tip to the validator) | Your max fee per gas | Fee you pay |
|---|---|---|---|---|
| 21,000 gas | 30 gwei | 2 gwei | 40 gwei | 0.000672 ETH |
| 21,000 gas | 30 gwei | 2 gwei | 40 gwei | 0.000672 ETH |
| 21,000 gas | 30 gwei | 2 gwei | 31 gwei | 0.000651 ETH |
- All values are your own inputs; the 30 gwei base fee and 2 gwei tip are the article's illustrative figures, not live fees.
- The base fee is paid first, so when your max fee is below base fee plus tip, the tip shrinks to what the max fee leaves over.
- The fee is charged on gas used, not on the gas limit, and it is charged even if the transaction fails.
This covers only Ethereum mainnet execution fees on your inputs: it leaves out rollup L1 data and operator fees, blob fees and the Glamsterdam repricing. It does not tell you whether a max fee below the base fee gets your transaction included.
Layer 2 fees and blobs
Rollups (layer 2 networks) execute transactions off mainnet and post the data back to Ethereum. Their fees come in two layers.
Blobs (EIP-4844, March 2024)
The Dencun upgrade went live on mainnet on 13 March 2024 at 13:55 UTC. Its EIP-4844 added "blobs", a cheaper place for rollups to put data. Blob gas is "independent of normal gas and follows its own targeting rule, similar to EIP-1559", so blobs have their own base fee, and that fee is burned. Each blob is 128 KiB and uses 131,072 blob gas. The EVM cannot read blob data, and nodes delete it after about 18 days (4,096 epochs).
Fusaka (December 2025) and blob capacity
Fusaka activated on mainnet on 3 December 2025 at 21:49:11 UTC. It added:
- PeerDAS, under which each full node holds about one-eighth of the blob data
- EIP-7918, a reserve price under the blob base fee, so the blob fee keeps responding to congestion instead of falling to near 1 wei
- EIP-7825, a cap of 16,777,216 (2^24) gas per transaction
- EIP-7935, under which clients shipped 60 million as the default block gas limit, up from 45 million
- EIP-7892, which allows "blob parameter only" forks to raise blob capacity between upgrades
Two of those forks followed. BPO1 (9 December 2025) raised the per-block blob target and maximum from 6 and 9 to 10 and 15. BPO2 (7 January 2026) raised them to 14 and 21.
Ethereum.org says Fusaka does not directly lower layer 1 gas fees. Its main effect is more blob space, which should make layer 2 transactions cheaper.
What a rollup actually charges
Fees vary by rollup. On OP Stack chains, a transaction fee has three parts:
- an execution gas fee, calculated like Ethereum's (base fee plus optional priority fee)
- an L1 data fee for posting your transaction's data to Ethereum, based on its compressed size and on Ethereum's base fee and blob base fee. It is charged automatically and the user cannot cap it.
- an operator fee that the chain operator can set
So a rollup fee still depends partly on demand on Ethereum mainnet.
How other chains price transactions
Bitcoin
Bitcoin has no gas. Fees depend on the byte size of the signed transaction. Since SegWit (BIP 141), size is measured as virtual size: transaction weight divided by four, rounded up. Blocks are capped at 4,000,000 weight units. The fee is not a separate field. It is whatever input value the outputs don't spend, and the miner who includes the transaction claims it. Miners generally rank transactions by fee per byte. The fees in a block are collected, together with the block subsidy, by the block's first transaction, the generation transaction.
Solana
Solana charges a base fee of 5,000 lamports per signature. Half is burned and half goes to the validator that produces the block. An optional priority fee is calculated as ceil(compute_unit_price × compute_unit_limit / 1,000,000) lamports, where the price is set in micro-lamports per compute unit, and all of it goes to the validator. Each instruction gets 200,000 compute units by default, and a transaction can use at most 1,400,000. As on Ethereum, "if the transaction fails, the fee is still charged."
Practical checks before you sign
- Read the max fee, not just the estimate. Your max fee per gas is the most you can pay per unit; anything above base fee plus tip is refunded.
- Don't trim the gas limit by hand on contract calls. If it runs out, the transaction fails and you are still charged.
- Expect the base fee to change between blocks. It can move up to 12.5% per block, so a fee quoted a few minutes ago may no longer hold during busy periods.
- On a rollup, count both layers. The L1 data fee moves with Ethereum's base fee and blob fee, not just the rollup's own activity.
- Watch for Glamsterdam's mainnet date. EIP-8037 and the other repricing EIPs will change how much gas some operations cost once they activate.
Limitations: protocol rules here come from official documentation and specifications as of 25 October 2026; live fee levels change every block and are not given here.
