EIP-3198: BASEFEE opcode Source

AuthorAbdelhamid Bakhta, Vitalik Buterin
TypeStandards Track
Requires 1559

Simple Summary

Add a BASEFEE (0x48) that returns the value of the base fee of the current block it is executing in.



The intended use case would be for contracts to get the value of the base fee. This feature would enable or improve existing use cases, such as:

  • Contracts that need to set bounties for anyone to “poke” them with a transaction could set the bounty to be BASEFEE + x, or BASEFEE * (1 + x). This makes the mechanism more reliable, because they will always pay “enough” regardless of market conditions.
  • Gas futures can be implemented based on it. This would be more precise than gastokens.
  • Improve the security for state channels, plasma, optirolls and other fraud proof driven solutions. Having the BASEFEE as an input allows you to lengthen the challenge period automatically if you see that the BASEFEE is high.


Add a BASEFEE opcode at (0x48), with gas cost G_base.

Op Input Output Cost
0x48 0 1 2


Backwards Compatibility

This EIP is backwards-compatible.

Test Cases

Nominal case

Assuming current block base fee is 7 wei. This should push the value 7 (left padded byte32) to the stack.

Bytecode: 0x4800 (BASEFEE, STOP)

Pc Op Cost Stack RStack
0 BASEFEE 2 [] []
1 STOP 0 [7] []

Output: 0x Consumed gas: 2

Security Considerations

Copyright and related rights waived via CC0.


Please cite this document as:

Abdelhamid Bakhta, Vitalik Buterin, "EIP-3198: BASEFEE opcode [DRAFT]," Ethereum Improvement Proposals, no. 3198, January 2021. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-3198.