Gas Fees Explained: Base Fee, Priority Fee, and Why a Transaction Gets Stuck

Not financial advice. Crypto assets carry risk and on-chain transactions are irreversible. Do your own research.

Two people send the same transaction a minute apart. One pays a modest fee and confirms immediately. The other pays several times as much, waits twenty minutes, and eventually gives up and cancels.

Neither did anything wrong in any obvious sense. They set different numbers in a screen most wallets hide behind an "advanced" toggle, and the numbers do different jobs.

The fee has two parts

Since EIP-1559, an Ethereum transaction's fee is built from two components, and confusing them is the source of nearly every gas mistake.

The base fee is set by the protocol, not by you. It moves up or down each block according to a formula based on how full the previous block was relative to a target size — rising when blocks are above the target and falling when they are below (EIPS/eip-1559).

And it is burned. It does not go to the validator. It is destroyed, which is the detail that makes the whole design work: nobody who orders transactions has an incentive to inflate it.

The priority fee is your tip to whoever builds the block, and it is the only part you actually bid. A transaction specifies a `max_priority_fee_per_gas` — the most it will give the validator to be included — and a `max_fee_per_gas`, the total cap covering the base fee and the tip together.

The rule that follows is the one worth remembering: senders always pay the base fee of the block their transaction ends up in, and your max fee is a ceiling, not a price. If you set a max fee well above the base fee, you are not overpaying — you are giving the transaction room to survive a rise while it waits.

Worked example. ethereum.org gives the fee formula as units of gas used x (base fee + priority fee), and states that "A standard ETH transfer requires a gas limit of 21,000 units of gas" (ethereum.org). With a base fee of 20 gwei and a 2 gwei tip, a transfer costs 21,000 x (20 + 2) = 462,000 gwei, or 0.000462 ETH: 0.00042 ETH is burned and 0.000042 ETH goes to the validator. If you had set a max fee of 40 gwei, you still pay 22 gwei per unit of gas, because the max is a ceiling, not a price.

How a generous ceiling still gets overtaken. In the EIP-1559 reference code the base fee can move by at most one eighth per block (BASE_FEE_MAX_CHANGE_DENOMINATOR = 8), which is 12.5% when a block is completely full; the gas target is the block gas limit divided by an elasticity multiplier of 2 (EIP-1559). Starting from 20 gwei, six completely full blocks in a row take the base fee to 20 x 1.125^6 = about 40.5 gwei, above that 40 gwei ceiling. Busy periods do not need to last long for a fee that looked comfortable to end up underwater.

Why a transaction gets stuck

Almost always: the max fee was set below where the base fee has since moved.

The base fee rises when blocks are consistently full. A transaction whose max fee sat comfortably above it when submitted can be underwater ten minutes later, and it cannot be included in a block whose base fee exceeds its own cap. So it waits, indefinitely, for congestion to fall back.

There is a second, more confusing cause: nonce order. Transactions from one account execute in strict sequence. A stuck transaction blocks every later one from that account regardless of what they pay, so a single underpriced transaction can freeze an account's activity entirely.

The two fixes are the same operation.

Both work because replacing a pending transaction requires outbidding it, which is why neither is free and why setting a sensible fee in the first place is cheaper than fixing it afterwards.

Gas limit is not the fee

The other number in the advanced panel is the gas limit, and it measures something completely different: how much computation the transaction is authorised to consume.

A simple transfer uses a small, fixed amount. A complex contract interaction uses far more, and the wallet estimates it.

Two consequences matter.

Setting the limit too low makes the transaction fail — and you still pay. The work was done up to the point it ran out, and that work is not refunded. This is the most expensive gas mistake available.

Raising the limit does not make it faster. You are not paying more; you are authorising more computation. Only the priority fee affects ordering.

Paying less, in order of effectiveness

Frequently Asked Questions

Do I get a refund if the base fee falls after I send?

You pay the base fee of the block your transaction is actually included in, not the one at the time you signed. If your max fee was higher than that, the difference is not charged. The max fee is a limit rather than a payment.

Where does the base fee go?

It is burned — destroyed rather than paid to anyone. Only the priority fee reaches the validator. This is a deliberate part of the EIP-1559 design, since a fee paid to the party choosing transaction order would create an incentive to inflate it.

Why did my transaction fail and still cost money?

Almost always because it ran out of gas. The computation performed before it ran out consumed real resources and is not refunded, so a failed transaction with too low a gas limit costs you the work done and delivers nothing.

Does a higher gas limit make my transaction confirm faster?

No. The gas limit authorises computation; the priority fee buys position. Raising the limit on a simple transaction changes nothing about how quickly it is included.

The summary

One number is set by the network and burned. One number is your bid. One number is a ceiling. One number is a computation budget, and getting it too low is the only way to pay for nothing at all.

Understand which is which and the "advanced" panel stops being intimidating — it becomes the difference between confirming in seconds for a sensible fee and watching a transaction sit pending while an account's whole queue backs up behind it.

Sources: EIP-1559 (eips.ethereum.org), read 19 August 2026; ethereum.org gas documentation and the EIP-1559 reference parameters, read 16 October 2026. Fee levels change constantly; the gwei figures in the worked examples are illustrative, not current prices.