Problem: I've upgraded my geth node to the latest version (1.9.0-unstable). The block gasLimit of the node is fixed at 5000:



When I try to send a transaction, I get the following error:

Error: exceeds block gas limit

Attempted fixes: I have tried to alter the default gasLimit value in the genesis.json:

"gasLimit": "0xffffffff"

From geth node command line option:

--targetgaslimit '9000000000000'

Point to note: On previous versions, i.e, before upgrading, the block gasLimit returned by the node was much higher and it let me deploy contracts and perform transactions.



3 Answers 3


As @fixanoid stated in his answer you can change the gas limit in the genesis.json.

But this isn't an optimal solution in my opinion. You are better off using a specific flag for your miner.

Geth has the --targetgaslimit flag that will cause your miner(s) to move step by step towards a given gas limit. Only a certain increase is allowed per block. Typically prev limit/1024. So it might take some time to get it where you want it to be. Obviously a larger change results in the block not being accepted.

Besides specifying the --targetgaslimit flag you also have to make your node --mine in your private blockchain (Obviously).

EDIT: How are you sending the transactions? What gas limit are you currently specifying? The minimum for a transaction is 21000. If you are invoking a contract with a fallback function even more gas is needed. Make sure you have enough ETH to pay for the gas.

The problem might be that the error message is flawed.

  • As stated in the question, neither genesis.json gasLimit setting nor miner flag is working with last go-ethereum version Commented Oct 30, 2019 at 8:15
  • You started mining?
    – cqx
    Commented Oct 30, 2019 at 9:23
  • Take a look at my edit as well. I am quite certain that the problem isn't really with you block gas limit directly.
    – cqx
    Commented Oct 30, 2019 at 10:14

3 things to try:

  • Avoid using unstable versions, switch to the last stable Elasa (v1.9.6)
  • You may have to increase the gas a bit when deploying contracts, because of new versions of solidity where gas calculation changes
  • Using a gas price oracle is sometimes needed

One way to do this is to set very high limit for gas in the genesis config file like so: "gasLimit": "0xE0000000". Alternatively, run a client optimized for private nets: https://github.com/jpmorganchase/quorum. Default gas limit is in billions.

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