GasUsed

Gas consumed by transaction execution

Try it Live

Run GasUsed examples in the interactive playground

GasUsed

GasUsed represents the actual amount of gas consumed by a transaction during execution. Found in transaction receipts as receipt.gasUsed.

Type Definition

type GasUsedType = bigint & { readonly [brand]: "GasUsed" };

Branded bigint representing gas consumed (always non-negative).

Gas Mechanics

Yellow Paper

Gas mechanics defined in Yellow Paper Section 6 (Transaction Execution):

• Gas vs Gas Price: Total cost = gasUsed × gasPrice (in Wei)
• Gas Limit: Maximum gas transaction can consume (gasUsed ≤ gasLimit)
• Refund: Unused gas refunded: (gasLimit - gasUsed) × gasPrice

Gas Ranges

• Minimum: 21,000 gas (simple ETH transfer)
• Typical: 50,000 - 200,000 gas (contract interactions)
• Maximum: Block gas limit (~30M on mainnet)

API

Constructors

from(value)

Create GasUsed from number, bigint, or string.

import { GasUsed } from '@tevm/primitives';

// From transaction receipt
const gasUsed = GasUsed.from(receipt.gasUsed);

// From bigint
const gas = GasUsed.from(51234n);

// From number
const gas2 = GasUsed.from(21000);

// From hex string
const gas3 = GasUsed.from("0xc822");

Throws: InvalidFormatError if value is negative.

Conversions

toNumber(gasUsed)

Convert to number.

const gasUsed = GasUsed.from(51234n);
GasUsed.toNumber(gasUsed); // 51234

toBigInt(gasUsed)

Convert to bigint (identity operation).

const gasUsed = GasUsed.from(51234n);
GasUsed.toBigInt(gasUsed); // 51234n

toHex(gasUsed)

Convert to hex string.

const gasUsed = GasUsed.from(51234n);
GasUsed.toHex(gasUsed); // "0xc822"

Comparisons

equals(gas1, gas2)

Check equality.

GasUsed.equals(51234n, 51234n); // true
GasUsed.equals(51234n, 21000n); // false

compare(gas1, gas2)

Compare values (-1, 0, 1).

GasUsed.compare(21000n, 51234n); // -1 (first < second)
GasUsed.compare(51234n, 51234n); // 0 (equal)
GasUsed.compare(51234n, 21000n); // 1 (first > second)

Utilities

calculateCost(gasUsed, gasPrice)

Calculate transaction cost in Wei.

const gasUsed = GasUsed.from(51234n);
const gasPrice = 20_000_000_000n; // 20 gwei

const cost = GasUsed.calculateCost(gasUsed, gasPrice);
// 1,024,680,000,000,000n Wei (0.00102468 ETH)

Common Gas Costs

Basic Operations

Operation	Gas Cost
Simple transfer	21,000
ERC20 transfer	~65,000
Uniswap V2 swap	~150,000
Contract creation	32,000+

Opcodes

Opcode	Gas Cost
SLOAD (cold)	2,100
SSTORE (set)	20,000
SSTORE (reset)	5,000
CALL	100+
CREATE	32,000+
LOG0	375
KECCAK256	30 + 6/word

See GasCosts for complete list.

Usage Examples

Calculate Transaction Cost

import { GasUsed } from '@tevm/primitives';

// Get from receipt
const receipt = await provider.getTransactionReceipt(txHash);
const gasUsed = GasUsed.from(receipt.gasUsed);

// Calculate cost
const gasPrice = receipt.effectiveGasPrice;
const cost = GasUsed.calculateCost(gasUsed, gasPrice);

console.log(`Gas used: ${GasUsed.toNumber(gasUsed)}`);
console.log(`Cost: ${cost} Wei`);

Compare Gas Usage

import { GasUsed } from '@tevm/primitives';

const tx1Gas = GasUsed.from(receipt1.gasUsed);
const tx2Gas = GasUsed.from(receipt2.gasUsed);

if (GasUsed.compare(tx1Gas, tx2Gas) > 0) {
  console.log('Transaction 1 used more gas');
}

Analyze Block Gas Usage

import { GasUsed } from '@tevm/primitives';

const block = await provider.getBlock(blockNumber, true);
let totalGas = 0n;

for (const tx of block.transactions) {
  const receipt = await provider.getTransactionReceipt(tx.hash);
  const gasUsed = GasUsed.from(receipt.gasUsed);
  totalGas += GasUsed.toBigInt(gasUsed);
}

console.log(`Block ${blockNumber} total gas: ${totalGas}`);
console.log(`Block utilization: ${(Number(totalGas) / 30_000_000 * 100).toFixed(2)}%`);

Block Gas Limit

Ethereum blocks have a gas limit (~30M on mainnet):

• Individual transaction: gasUsed ≤ gasLimit (set in tx)
• Block total: Σ gasUsed ≤ blockGasLimit
• Full block: High priority transactions fill blocks

EIPs

• EIP-2929: Gas cost increases for state access opcodes
• EIP-1559: Fee market change (doesn’t affect gasUsed, but introduces base fee)
• EIP-3529: Reduction in gas refunds (affects net cost but not gasUsed)

See Also

• GasEstimate - Estimate gas before execution
• GasRefund - Gas refunds after execution
• GasCosts - Gas cost constants
• Yellow Paper Section 6 - Transaction execution