Cross-chain · Avalanche C-Chain → Base

Swap AVAX from Avalanche C-Chain to WETH on Base

Swap AVAX from Avalanche C-Chain to WETH on Base. Native AVAX leaves C-Chain, and Base WETH is what can arrive. The predeploy is an ERC-20, not the ETH that pays gas.

AVAX is 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE on Avalanche C-Chain, chain id 43114. Snowtrace shows native gas leaving. WETH is 0x4200000000000000000000000000000000000006 on Base, chain id 8453. Basescan is the check. That hex is a common predeploy, so a balance on another rollup is not this balance. You do not receive native ETH, and you do not receive WBTC.

Diagram for Swap AVAX from Avalanche C-Chain to WETH on Base
AVAX leaves Avalanche C-Chain. WETH is what can arrive on Base.

A shared predeploy hex is not a shared balance

Seeing 0x4200000000000000000000000000000000000006 on another L2 does not credit chain id 8453. Basescan is the only explorer for this arrival. Arbitrum WETH is 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1, a completely different address. Polygon WETH is different again. Ethereum's WETH, 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2, lives on chain id 1 with about 12 second blocks and Etherscan. Paste the Base predeploy only.

Leave AVAX for the C-Chain fee

The sentinel is not an approval target. It is the coin that also pays the network. Drain it and the swap never broadcasts. X-Chain AVAX is the wrong chain inside Avalanche, not a backup balance. Snowtrace on 43114 should show the debit from a C-Chain account. If the wallet network is off, fix it before you type the amount you are willing to sell.

WETH on Base cannot start the next transaction

Gas is ETH. Base is an L2, and the fee is still ETH, not AVAX and not the wrapper. If you are bridging because a button said insufficient funds, read whether it wanted ETH or WETH. The native route answers the first. This page answers the second. Arriving in WETH with an empty ETH line recreates the error you were trying to clear.

Do not detour through Base for a pool that lives elsewhere

If the contract you must call is on Ethereum or Arbitrum, Base WETH is the wrong inventory. Bridge only when this predeploy is the token the app named. The steps are in how to bridge assets between chains. Judge the minimum WETH, not a guessed wait. WBTC is a separate claim on bitcoin and is not what Avalanche is selling into here.

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 AVAX from Avalanche C-Chain to WETH on Base?

AVAX is 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE on Avalanche C-Chain, chain id 43114. Snowtrace shows native gas leaving.

Is Base WETH the same token as WETH on Arbitrum?

No. This route delivers 0x4200000000000000000000000000000000000006 on Base, chain id 8453. Arbitrum WETH is a different contract on chain id 42161. Check Basescan. AVAX left C-Chain as native gas. The wrapper cannot pay Base fees, so hold ETH as well. The quote minimum is the floor, and a thin floor is a reason to stop.

Do I approve AVAX before it leaves?

No. 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE is native AVAX on chain id 43114, not an ERC-20. Snowtrace shows the send. X-Chain balances do not qualify. Leave enough AVAX to pay the fee, because the asset you sell is also the asset that pays for the transaction. A block interval is not a delivery time for the bridge.

When should I avoid AVAX to Base WETH?

When you needed native ETH for gas, Circle USDC, or a WETH contract on another chain. The predeploy on a different rollup is not this balance. Ethereum mainnet WETH is chain id 1 and uses Etherscan. If the pool is not on Base, this hop is the wrong job. Read the minimum first.

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