How to set gas in MetaMask
Where the custom fee fields are and what each one does.
Updated
Short answer
On the confirmation screen, open the network fee row and choose Advanced to get the editable fields instead of the presets. Set the priority fee to match what recent blocks paid, set the max base fee above the current base fee with room to spare, and leave the gas limit alone.
MetaMask picks fees for you and is usually close enough. Two situations make it worth overriding: you are in no hurry and would rather pay less than the default, or the transaction has to land in the next block or two and the default will not get you there. Everything else is fine on automatic.
Finding the fields
MetaMask has moved these controls between versions, so treat the wording below as a guide rather than an exact script.
- Start the transaction as normal and wait for the confirmation screen.
- Find the network fee row and open its edit control, labeled Market or shown as a small edit icon next to the estimate.
- Choose Advanced to get the editable fields instead of the low, market and aggressive presets.
- Enter your values, save, then confirm.
What each field does
Max base fee
The name is misleading. This field sets the max fee per gas from EIP-1559, meaning the ceiling on base fee and tip together, not a cap on the base fee alone. You are not offering this number, you are agreeing not to exceed it, and the base fee is subtracted from it first.
Set it above the current base fee with room to spare. Doubling the current base fee is a reasonable default and costs nothing extra if the fee stays flat. Set it too close and a single busy block leaves your transaction pending until the base fee falls back under your ceiling.
Priority fee
The tip to the block proposer, and the only number that competes for position. When blocks are running under target, a small tip is sufficient. When you are racing other people for the same block, this is the number to raise, not the max base fee.
For the number itself, match what recent blocks paid rather than picking a round figure. The tracker shows the median tip and the percentiles either side of it, and how much to tip goes through what going over or under is worth.
Gas limit
Leave it alone in almost every case. MetaMask fills it by simulating the transaction, and unused gas is never charged, so a limit above what the transaction needs costs you nothing. Lowering it below what the transaction needs makes it run out of gas and revert, and you still pay for the work it did before failing.
If a transaction gets stuck
A pending transaction can be replaced by resending it with the same nonce and a higher fee, which is what MetaMask's speed up and cancel buttons do. Nodes generally require a meaningful increase before they will accept the replacement, on the order of 10%, so a token bump will be ignored.
Until it clears, everything you send from that account queues behind it. Nonces are processed in order, so a single underpriced transaction blocks the whole account rather than just itself.