Gas fees are essential for executing transactions on the Ethereum network. In MetaMask, these fees are calculated based on a few key components, especially after the implementation of EIP-1559.

Gas Fee Components

• Base Fee: This is a minimum fee set by the network for including a transaction in a block. It adjusts based on network congestion.
• Priority Fee (Tip): This is an optional fee that users can add to incentivize miners to prioritize their transaction. The higher the tip, the faster the transaction is likely to be processed.
• Gas Limit: This is the maximum amount of gas units that a transaction can consume. For simple transactions, this is typically set at 21,000 units.

Gas Fee Calculation Formula

The total gas fee paid for a transaction can be calculated using the following formula:

Gas Fee = (Base Fee + Priority Fee) x Gas Used

For example, if the base fee is 10 gwei, the priority fee is 2 gwei, and the transaction uses 21,000 gas units, the calculation would be:

Gas Fee = (10 gwei + 2 gwei) x 21,000 = 252,000 gwei

Sample Code for Gas Fee Estimation

Here’s a simple JavaScript function that estimates the gas fee for a transaction:

function estimateGasFee(baseFee, priorityFee, gasUsed) {
    const totalGasFee = (baseFee + priorityFee) * gasUsed;
    return totalGasFee; // returns the total gas fee in gwei
}

// Example usage
const baseFee = 10; // in gwei
const priorityFee = 2; // in gwei
const gasUsed = 21000; // for a simple ETH transfer

const estimatedFee = estimateGasFee(baseFee, priorityFee, gasUsed);
console.log(`Estimated Gas Fee: ${estimatedFee} gwei`);

Conclusion

Understanding how gas fees are calculated in MetaMask is crucial for users to manage their transaction costs effectively. By adjusting the priority fee and being aware of the base fee fluctuations, users can optimize their transactions for speed and cost.