Transaction Fees on Scroll L2
Scroll Alpha Testnet fees are notably lower than on its supporting layer. Being an L2 rollup also means that the total transaction cost depends on the L1 since it has to be settled on Ethereum for final security.
From the perspective of users and developers, gas fees on Scroll work very similarly to Ethereum mainnet. Scroll’s zkEVM equivalence allows all existing tools, wallets, and code to work the same.
But, under the hood, Scroll Alpha introduces some new dimensions into transaction fee calculation. The gas fee of a transaction can be dissected into several parts:
- Calculated in the same manner as on the L1, with the formula being
gas_price * gas_used
- This additional fee covers sending data to L1 for data availability.
- It's calculated based on the size of the transaction calldata
- It is deducted automatically from the user’s ETH Balance on Scroll for that user’s transaction
At a high level, we can describe the L2 fee as the cost of executing your transaction on the L2 sequencer and the L1 fee as the cost of committing that transaction onto L1 and securing the network. The latter part is one of the things that makes Scroll an L2.
In summary, we can say that
totalTxFee = l2Fee + l1Fee, all denominated in ETH.