I am using Remix to write a smart contract. One of the functions checks the block number before paying out a user:

contract MyContract {
  uint lastBlockNumber;

  // ...

  function setLastBlockNumber(uint number) {
    lastBlockNumber = number;

  function claim() public {
    if (block.number >= lastBlockNumber + 10) {

I don't see a way to set the block number in Remix so that I can test that if 10 blocks have passed it will actually pay out the balance. Is this possible, and if so how?

(Background: I'm coming to Solidity from JavaScript. I have noticed a block number field in the Debugger tab, but as far as I can tell that's a way of selecting a transaction to debug. I don't see anything in the Remix documentation about incrementing or setting the block number.)

  • I don't think you can do this with the JavaScript VM embedded in Remix, but you can do it with ganache. – smarx Mar 5 '18 at 4:34

I wouldn`t use Remix as a way of actual development. Instead, try using truffle which has ganache (testrpc) integrated. To check the blocknumber however use block.number. Which can be found: http://solidity.readthedocs.io/en/develop/units-and-global-variables.html.


truffle and ganache enable you to move forward in block creation.

in your it test block use :

await increaseTime(your duration in time not in block);

of course ganache accept specifing the block time creation exp

ganache-cli -b 3 //3 seconds

then define the increaseTime function as follow :

module.exports.increaseTime = function increaseTime(duration) {
  const id = Date.now();

  return new Promise((resolve, reject) => {
        jsonrpc: "2.0",
        method: "evm_increaseTime",
        params: [duration],
        id: id
      err1 => {
        if (err1) return reject(err1);

            jsonrpc: "2.0",
            method: "evm_mine",
            id: id + 1
          (err2, res) => {
            return err2 ? reject(err2) : resolve(res);

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