I have 2 contracts which take each other's addresses as constructor arguments. Here's the pseudocode,

constructor A(address B)
constructor B(address A)

I am deploying contracts using

const Contract = await ethers.getContractFactory(contractName)
const contract = await Contract.deploy(...args)
await contract.deployed()

console.log(contract.address) // I want to find address before, not after deployment

How to find the contract address before deployment?

3 Answers 3


@ethersproject/address provides a getContractAddress() function to find future deployment address.

const { ethers } = require('hardhat')
const { getContractAddress } = require('@ethersproject/address')

async function main() {
  const [owner] = await ethers.getSigners()

  const transactionCount = await owner.getTransactionCount()

  const futureAddress = getContractAddress({
    from: owner.address,
    nonce: transactionCount

Contract addresses are deterministic and need the deployer address and nonce to pre-compute it.

You can use the following code to determine the contract address before deployment.

const rlp = require('rlp');
const keccak = require('keccak');
const web3 = require('web3')

const encodedData = rlp.encode([
  '0x6c4465dc4dc3466c5736142ce8e12917a1e22c4', // address from which contract is to be deployed
  web3.utils.toHex(4) // hex encoded nonce of address that will be used for contract deployment

const contractAddress = `0x${keccak('keccak256').update(encodedData).digest('hex').substring(24)}`

But I will recommend adding a method in the second contract and update the contract address later. Make sure that the function is callable only once, this will be a more reliable approach.

Sample code:

pragma solidity 0.6.8;

contract A {
    address b;
    function addSecondaryContract(address _b) public /* onlyOwner */ {
        require(b != address(0), "contract already added");
        b = _b;

contract B {
    address a;
    constructor(address _a) public{
        a = _a;
  • 1
    Thank you for your answer. I've found a helper function from Ethers which finds the future address idiomatically. Commented May 11, 2021 at 17:19
  • @secretshardul what was the helper function?
    – Kwame
    Commented Jun 2, 2022 at 12:11

Based on Prashant's answer, I created Soladd -- a web tool for finding smart contract address before deployment, just based on wallet address -- where nonce is fetched from chain but can also be set manually, if required. 💯

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