How to get a contract's balance in Solidity?

Question

How do I get the balance of a contract with solidity? I know geth has web3.eth.getBalance(), but that's to get the contract balance after it has been deployed.

Is there a standard way of doing this, or do I have to have a separate var that uint256 that keeps track of the total balance?

Answer 1

You can do this by calling address.balance. To get the contract's balance, just do this.balance. Read the docs.

Update: As of Solidity ^0.4.24, you need to do:

address(this).balance

(Copied from answer by Paul Berg)

Answer 2

Small update from my side:

You want to use the following, address(this).balance;

Answer 3

As of Solidity ^0.4.24, you need to do:

address(this).balance

You can see an example here.

Alternatively, if you need to read the balance of a separate contract:

address(contractVar).balance

Answer 4

In case of invalid opcode, use a local variable of type address payable as workaround:

        address payable self = address(this);
        uint256 balance = self.balance;

In solidity 0.5.14, I get an invalid opcode, debugging showed me, that it is exactly here:

address(this).balance

Test result:

     Error: Returned error: VM Exception while processing transaction: invalid opcode
     at PromiEvent (node_modules/truffle/build/webpack:/packages/contract/lib/promievent.js:6:1)                                                              
      at TruffleContract.destroy (node_modules/truffle/build/webpack:/packages/contract/lib/execute.js:158:1)                                                 
      at Context.it (test/1_PactaTest.js:108:17)                                                                                                              
      at web3.eth.getBlockNumber.then.result (node_modules/truffle/build/webpack:/packages/core/lib/testing/testrunner.js:161:1)                              
      at <anonymous>                                                                                                                                          
      at process._tickCallback (internal/process/next_tick.js:188:7)                                                                                          

Debugging:

debug(development:0x7655ecf8...)> 

Pacta.sol:

115:     // move whole balance to the owner
116:     function withdraw() public managers isActive {
117:         uint256 part = address(this).balance / beneficiaries.length;
                            ^^^^^^^^^^^^^^^^^^^^^                        

debug(development:0x7655ecf8...)> 

Transaction halted with a RUNTIME ERROR.

This is likely due to an intentional halting expression, like assert(), require() or revert(). It can also be due to out-of-gas exceptions. Please inspect your transaction parameters and contract code to determine the meaning of this error.

Answer 5

uint256 contractBalance = address(this).balance;

Answer 6

I think the code should looks like this:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract Balance {

  function balance() public returns (uint256){
    return payable(address(this)).balance;
  }
}

Answer 7

address(this) give address of current deployed smart contract

<address>.balance give balance of any address. e.g. 0x9812j3....kh1298n.balance

to get balance of contract from contract itself. use this code:

function getBalance() public view returns(uint){
   return address(this).balance;
}

to get balace of any contracts/person of the whole blockchain, use this code:

function getBalance(address ContractAddress) public view returns(uint){
    return ContractAddress.balance;
}

ref: https://docs.soliditylang.org/en/latest/control-structures.html?highlight=address%20initial#salted-contract-creations-create2

Answer 8

Create a simple function which accept the address and in return it just return back amount of eth u hold

function balance(address owner) public view returns(uint accountBalance)
{
   accountBalance = owner.balance;
}

Answer 9

Important thing is add this two agregators to your function public and view for show it and access it to every one.

//                       |      |
//                       v      v
function showBalance() public view returns(uint) {
   return address(this).balance;
}

Regards