11

Do these have a separate cost?

sstore(1, 10) # first time adding a value to storage with this key
sstore(1, 20) # changing the value in storage.

I looked for a list of gas costs / opcodes, and the only one I could find (https://docs.google.com/spreadsheets/d/1m89CVujrQe5LAFJ8-YAUCcNK950dUzMQPMJBxRtGCqs/edit#gid=0) is a year old. It seems to say that modifying storage is cheaper, but I'm not sure if these values are outdated.

1 Answer 1

14

Yes, using storage has different gas costs:

20,000 gas when a value is set to non-zero from zero; 5,000 gas when writing to existing storage or setting a value to zero; and a 15,000 gas refund when a non-zero value is set to zero.

The Yellow Paper is the underlying source.

EIP-2200 has further explanations.

Related question: Does an SSTORE where the new value is the same as the existing value cost gas?

2
  • 1
    Due to EIP-3529, I don't think that this answer is up to date anymore. In particular, the gas refund is much lower than 15,000 now. Dec 20, 2022 at 18:01
  • 1
    @PaulRazvanBerg Agree, there's been plenty of changes to gas costs. I recall a related question I updated more than a year ago with the different EIPs, I'll try to find. Another approach is I could put a bounty here to try to elicit a well-written answer. Precise answer to this question could keep changing as the EVM evolves, so attracting more views here might not be best.
    – eth
    Dec 26, 2022 at 7:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.