Table of Contents for Max contract size on Ethereum

“Spurious Dragon” was the 4th hard fork, at block num 2,675,000, back in 2016. It introduced a new contract code size limit of 24576 bytes.

You can see more about this at https://github.com/ethereum/EIPs/blob/master/EIPS/eip-170.md

If block.number >= FORK_BLKNUM, then if contract creation initialization returns data with length of more than MAX_CODE_SIZE bytes, contract creation fails with an out of gas error.

You may have seen the following error, telling you about this:

Warning: Contract code size exceeds 24576 bytes (a limit introduced in Spurious Dragon). This contract may not be deployable on mainnet. Consider enabling the optimizer (with a low “runs” value!), turning off revert strings, or using libraries.

How to reduce Solidity contract sizes

This is a list of ways to reduce your Soldiity smart contract code size.

• remove unused code/functions
• avoid creating variables (inlining variables can reduce size)
• create smaller error messages
• separate your contracts into their own contracts
• try changing the optimizer settings
• use proxies, use delegatecall
• use libraries

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