For educational purposes only; not investment advice. Investing may result in loss.
Direct answer
The EIP-1559 base fee is the protocol-set minimum price per unit of execution gas in an Ethereum block. It rises when the parent block uses more than its gas target, falls when the parent uses less, and stays unchanged at the target. The base fee paid for consumed gas is burned rather than paid to the validator.
Each block has one base_fee_per_gas, known before transactions in that block execute. The target is half the block gas limit under Ethereum’s elasticity multiplier of 2, so blocks can absorb short demand bursts up to the gas limit while the adjustment rule pushes average use back toward the target.
A Type 2 transaction supplies max_fee_per_gas and max_priority_fee_per_gas. The first caps the total price per gas; the second caps the validator tip. A high cap is not automatically charged in full: the sender pays the block base fee plus the permitted tip for gas actually consumed.
- Fiat equivalent
- $1.39
- Base fee
- 22 gwei
Outputs are educational approximations. They exclude venue rules, taxes, latency, oracle behavior, and other protocol-specific parameters unless shown.
How it works
1. Derive the next block’s base fee
Let B be the parent block’s base fee, G its gas used, and T = parent gas limit / 2 its gas target. Ethereum applies integer arithmetic:
- At target:
G = T, soB_next = B. - Above target:
B_next = B + max(floor(B * (G - T) / T / 8), 1 wei). - Below target:
B_next = B - floor(B * (T - G) / T / 8).
A full parent block has G = 2T, so the increase is at most 12.5% for that step; an empty parent block produces a decrease of up to 12.5%. The minimum upward change of 1 wei matters only when integer division would otherwise round an above-target increase to zero.
2. Apply the transaction’s fee caps
For a Type 2 transaction included in a block, the effective tip and price are:
effective_priority_fee = min(max_priority_fee_per_gas, max_fee_per_gas - base_fee_per_gas)effective_gas_price = base_fee_per_gas + effective_priority_feetransaction_fee = gas_used * effective_gas_price
The transaction cannot be included if max_fee_per_gas < base_fee_per_gas. When the max-fee cap leaves less room than the requested tip, the effective tip is reduced. The base-fee portion is burned, while the priority-fee portion goes to the block’s fee recipient.
3. Reconcile the receipt
Read baseFeePerGas from the containing block and gasUsed plus effectiveGasPrice from the receipt. Check that gasUsed * effectiveGasPrice matches the balance change attributable to execution fees. Gas not consumed from the transaction gas limit is not charged, and unused room under max_fee_per_gas is not a separate payment.
Worked example
Assume the parent block has a 15,000,000 gas target, uses the full 30,000,000 gas limit, and has a 30 gwei base fee. The maximum step is 30 gwei * 12.5% = 3.75 gwei, so the next block’s base fee is 33.75 gwei (ignoring only integer-rounding detail below 1 wei).
Now suppose a simple transfer in that next block uses 21,000 gas, with max_fee_per_gas = 50 gwei and max_priority_fee_per_gas = 2 gwei:
- Effective priority fee:
min(2, 50 - 33.75) = 2 gwei. - Effective gas price:
33.75 + 2 = 35.75 gwei. - Total execution fee:
21,000 * 35.75 = 750,750 gwei = 0.00075075 ETH. - Burned base fee:
21,000 * 33.75 = 708,750 gwei = 0.00070875 ETH. - Validator tip:
21,000 * 2 = 42,000 gwei = 0.000042 ETH.
The 50 gwei max fee is a ceiling, not the price charged. If the base fee rose above 50 gwei before inclusion, this transaction would remain ineligible until the base fee fell or the sender replaced it with a higher cap.
Risks
- A wallet estimate uses recent blocks; a demand shock can raise the base fee before inclusion.
- A low
max_fee_per_gascan leave a transaction pending, while an unnecessarily high cap increases the authorization ceiling even though it is not normally paid in full. - Reverted execution still consumes gas, so a failed application action can still burn base fee and pay a tip.
- A larger tip may improve inclusion priority, but it does not guarantee a position, execution success, or finality.
- Wallet, RPC, explorer, or node data can be stale or inconsistent; verify the containing block and receipt together.
- Ethereum mainnet parameters do not automatically describe every rollup or EIP-1559-like chain; elasticity, denominators, minimum fees, and extra fee components may differ.
- Base-fee burning does not guarantee that ETH supply falls; net supply also depends on protocol issuance and total burn.
- Do not confuse transaction
gas_limit, block gas limit, gas target,gas_used, price per gas, and total fee; they are different quantities.
Common misconceptions
Myth 1: The current block decides its own base fee
The parent block’s gas use determines the next block’s base fee. Transactions in the current block face a base fee already fixed in its header.
Myth 2: Every above-target block raises the base fee by 12.5%
The change is proportional to the distance from target. 12.5% is the maximum step at the full gas limit under the standard Ethereum parameters.
Myth 3: max_fee_per_gas is always paid
It is a cap. The effective price is the block base fee plus the allowed priority fee, limited by that cap, multiplied by gas actually used.
Myth 4: The validator receives the entire gas fee
The base-fee portion is burned. The validator’s execution-layer fee revenue is the effective priority fee, not the full effective gas price.
Myth 5: Burning the base fee makes every transaction deflationary
A transaction burns ETH, but whether total ETH supply decreases over a period depends on aggregate burn relative to aggregate issuance.
Related topics
Sources
- EIP-1559: Fee market change for ETH 1.0 chain - Ethereum Improvement Proposals (accessed: 2026-08-20)
- Ethereum gas and fees: technical overview - ethereum.org (accessed: 2026-08-20)