# EIP-1559 & Gas Estimation 

By [taihucao](https://paragraph.com/@taihucao) · 2023-04-10

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EIP-155
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*   Replay Attack Protection
    
*   ChainID
    

> [https://chainlist.org/](https://chainlist.org/)

EIP-1559 (London)
-----------------

> [https://eips.ethereum.org/EIPS/eip-1559](https://eips.ethereum.org/EIPS/eip-1559)

### Why EIP-1559?

*   Background:
    
    *   ETH token-nomic (Inflation, Deflation)
        
    *   Miner income
        
        *   Block Reward (also, Uncle Block Reward)
            
        *   Transaction Fee (Gas) -- reached nearly half of Block Reward - Security Issue
            
        *   MEV
            
*   Issues
    
    *   Gas War
        
    *   Congestion
        
    *   Security threat by Miners
        

### Mainly About

*   Base Fee -- Burn
    
*   Priority Fee -- Miner
    
*   Max Fee -- **Remaining Part** will be refund to sender
    

### Transactions on explorer

Legacy TX:

[https://etherscan.io/tx/0x177767d9398486c932d8b1e289e55a8e3b843a381b7470920a4339de775f4c0f](https://etherscan.io/tx/0x177767d9398486c932d8b1e289e55a8e3b843a381b7470920a4339de775f4c0f)

EIP-1559 TX:

[https://etherscan.io/tx/0x84c1a231c787cd3b4f031cfeb6a1d66bfb0a6e226e438e3accfda7be49e4cd6b](https://etherscan.io/tx/0x84c1a231c787cd3b4f031cfeb6a1d66bfb0a6e226e438e3accfda7be49e4cd6b)

### Remaining Issues

*   Gas War
    
*   NO Gas CELING
    

### How to set up gas provider for EIP-1559?

Sample Code with Web3j:

    // Get baseFee from last block
    BigInteger baseFeePerGas = web3j.ethGetBlockByNumber(DefaultBlockParameterName.LATEST, false).send().getBlock().getBaseFeePerGas();
    BigInteger maxPriorityFeePerGas = web3j.ethMaxPriorityFeePerGas().send().getMaxPriorityFeePerGas();
    BigInteger maxFeePerGas = baseFeePerGas.add(maxPriorityFeePerGas);
    

Gas Estimation
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### What and Why?

Before the execution, would like to how much gas the transaction need to get successfully executed.

For better gas preparation;

For more reasonable fee structure;

For avoid most TX execution failures;

etc.

### How?

Sample Code with Web3j:

    private static ContractEIP1559GasProvider buildGasProviderForApprove(Web3j web3j, String fromAddress,
                                      String scAddress, String spender, BigInteger amountInWei) throws IOException {
        long chainId = web3j.ethChainId().send().getChainId().longValue();
    
        BigInteger baseFeePerGas = web3j.ethGetBlockByNumber(DefaultBlockParameterName.LATEST, false).send().getBlock().getBaseFeePerGas();
        BigInteger maxPriorityFeePerGas = web3j.ethMaxPriorityFeePerGas().send().getMaxPriorityFeePerGas();
    
        BigInteger maxFeePerGas = baseFeePerGas.add(maxPriorityFeePerGas);
    
        BigInteger gasLimit = estimateApproveGasLimit(web3j, fromAddress, scAddress, spender, amountInWei, maxFeePerGas, maxPriorityFeePerGas);
        return new StaticEIP1559GasProvider(chainId, maxFeePerGas, maxPriorityFeePerGas, gasLimit);
    }
    
    private static BigInteger estimateApproveGasLimit(Web3j web3j, String fromAddress, String scAddress, String spender, BigInteger amountInWei,
                                                      BigInteger maxFeePerGas, BigInteger maxPriorityFeePerGas) throws IOException {
        Function function = new org.web3j.abi.datatypes.Function(
                "approve",
                Arrays.<Type>asList(new org.web3j.abi.datatypes.Address(160, spender),
                        new org.web3j.abi.datatypes.generated.Uint256(amountInWei)),
                Collections.<TypeReference<?>>emptyList());
    
        EthGetTransactionCount ethGetTransactionCount = web3j.ethGetTransactionCount(fromAddress, DefaultBlockParameterName.PENDING).send();
        BigInteger nonce = ethGetTransactionCount.getTransactionCount();
        long chainId = web3j.ethChainId().send().getChainId().longValue();
    
        Transaction transaction = new Transaction(fromAddress, nonce, null, BigInteger.valueOf(4300000),
                scAddress, BigInteger.ZERO, FunctionEncoder.encode(function), chainId, maxPriorityFeePerGas, maxFeePerGas);
        BigInteger gasLimit = web3j.ethEstimateGas(transaction).send().getAmountUsed();
    
        return gasLimit;
    }

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*Originally published on [taihucao](https://paragraph.com/@taihucao/eip-1559-gas-estimation)*