Cross-chain · Arbitrum One → Base

Swap USDC from Arbitrum One to WETH on Base

Swap USDC from Arbitrum One to WETH on Base. Circle USDC leaves Arbitrum One and Base WETH arrives on Base.

Spend 0xaf88d065e77c8cC2239327C5EDb3A432268e5831, Circle USDC, on Arbitrum One. Arbiscan, chain id 42161, not Nova. Fee in ETH. Receive the Base WETH predeploy at 0x4200000000000000000000000000000000000006. Basescan should show that contract. It is not native ETH, not the sentinel, and not Ethereum WETH at 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2. Base is chain id 8453, an L2. Blocks about every 2 seconds. That is not a delivery promise.

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

The 0x4200 predeploy is Base-specific

OP-stack chains share the WETH address 0x4200000000000000000000000000000000000006, and that does not make the balance shared. This quote can credit the predeploy on chain id 8453 only. The same hex on another rollup is a different ledger. Ethereum's canonical WETH uses a completely different address. If a pool on Base asks for WETH, this contract is the one it usually means. If it asks for gas, it means the sentinel instead.

Wrapped output cannot pay Base gas

Base fees are native ETH. Receiving WETH does not create that balance. If the Base account has never held ETH, you can own WETH and still be unable to unwrap or transfer it. Unwrapping needs gas first. This route is the wrong shape when the next click is a plain Base transfer. It is the right shape when a contract calls transfer on the predeploy.

Dollars against wrapped ether

Six-decimal Circle USDC goes in. Eighteen-decimal WETH can come out. The minimum is a price, and it expires. How cross-chain bridges work covers the hop between Arbitrum One and Base. It does not turn USDC into a one-for-one wrap. USDC.e on the source will not be accepted as the spend.

Wrong chain or wrong wrapper

Stop if you need native ETH on Base for gas. Stop if you need Ethereum mainnet. Stop if you need Base USDC at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913. Stop on Nova. Stop if you meant to wrap ETH you already hold on Base, which is a local call and does not involve Arbitrum USDC.

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 USDC from Arbitrum One to WETH on Base?

Spend 0xaf88d065e77c8cC2239327C5EDb3A432268e5831, Circle USDC, on Arbitrum One. Arbiscan, chain id 42161, not Nova.

Is Base WETH the Ethereum WETH contract?

No. Base uses 0x4200000000000000000000000000000000000006. Ethereum WETH is 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2. You spend Circle USDC at 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 on Arbitrum One. Confirm the predeploy on Basescan, chain id 8453. It is an L2 contract, not a mainnet balance, and it does not pay gas. Confirm that address on the explorer before you sign, and refresh the quote if it has expired.

Can I unwrap Base WETH with a zero ETH balance?

No. The unwrap is a transaction, and Base charges native ETH, the sentinel 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE. This route does not credit that sentinel. If the account has no Base ETH, fund gas first or choose a route that delivers native ETH. About 2 seconds is a block interval, not an unwrap.

Does the shared 0x4200 address mean every L2 shares my WETH?

No. The predeploy address is reused by design on OP-stack chains, but balances are per chain id. A credit on Base does not appear on another rollup that uses the same hex. Check chain id 8453 on Basescan. Arbitrum WETH is a different address entirely, 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1, and you are not selling it.

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