Cross-chain · Arbitrum One → Base

Swap ETH from Arbitrum One to WETH on Base

Swap ETH from Arbitrum One to WETH on Base. Native ETH leaves Arbitrum One and Base WETH arrives on Base.

Spend native ETH, sentinel 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE, on Arbitrum One. Arbiscan, chain id 42161, not Nova. Reserve the fee. Receive 0x4200000000000000000000000000000000000006 on Base. Basescan should show that predeploy. It is not Base gas and not Ethereum WETH. Chain id 8453 is an L2. Blocks are about 2 seconds. A local wrap on Arbitrum would not create this credit.

Diagram for Swap ETH from Arbitrum One to WETH on Base — ETH leaves Arbitrum One. WETH is what can arrive on Base.

Wrapping locally never leaves Arbitrum

Deposit into 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1 and you stay on chain id 42161 with Arbitrum WETH. This route can credit the Base predeploy instead. The amount is a quote, not the one-wei-for-one-wei result of a local deposit, because the hop has costs. Read the minimum. Do not paste the Arbitrum WETH address into Basescan and expect a balance.

The predeploy is not the gas row

0x4200000000000000000000000000000000000006 cannot pay Base fees. The sentinel on chain id 8453 can. If this Base wallet has no ETH, the new WETH is stuck until gas arrives. You also cannot spend every wei on Arbitrum, because that chain's fee comes from the same balance you are selling. Two gas constraints, and the output helps with neither until you unwrap, which itself needs Base ETH.

Mainnet WETH is a different hex

0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 is Ethereum. This page never targets chain id 1. Base is the L2, chain id 8453. The 0x4200 address is reused on other OP-stack chains and the balances are not pooled. Check the chain id in the wallet header before you decide the credit is missing.

Wrong if you needed spendable Base ETH

Choose the native output if the next action is a fee. Choose a USDC output if you wanted dollars. This page is wrong for WETH you already hold on Arbitrum, wrong for Nova, and wrong for a mainnet wrap. It is also wrong if you thought Base ETH and Arbitrum ETH were one balance that wrapping could reshuffle.

Legal

Risk disclosure

XAUConnect is a non-custodial swap aggregator. Digital assets are volatile and may lose value rapidly. Content on this page is educational and not investment advice. Verify every contract address on the official block explorer before approving a transaction.

Frequently asked questions

What is the best way to swap ETH from Arbitrum One to WETH on Base?

Spend native ETH, sentinel 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE, on Arbitrum One. Arbiscan, chain id 42161, not Nova.

Is this just wrapping ETH?

No. A wrap on Arbitrum One credits 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1 and stays on chain id 42161. This route spends native ETH, sentinel 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE, and can credit Base WETH at 0x4200000000000000000000000000000000000006. Check Basescan. It is an L2 predeploy, not Ethereum WETH. Confirm that address on the explorer before you sign, and refresh the quote if it has expired.

Will Base WETH pay gas on Base?

No. Gas is native ETH on chain id 8453. The predeploy is an ERC-20. Unwrapping needs ETH already in the account, which this route does not provide. About 2 seconds is a Base block interval, not a gas credit. Reserve ETH on Arbitrum One as well, because you are selling the source fee coin.

Does 0x4200 on another chain show this balance?

No. The address is a shared predeploy pattern. The ledger is per chain. Only chain id 8453 can show this credit, on Basescan. Another rollup with the same hex is a different wallet balance. Nova is not Base, and it is not the source network either.

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