Is Avalanche already built into MetaMask?

Yes. MetaMask ships Avalanche in its popular networks list. Open the network selector, choose "Add network", and enable Avalanche with one click. Manual entry is only needed on older versions or for the Fuji testnet.

What is the Avalanche chain ID for MetaMask?

The Avalanche C-Chain mainnet chain ID is 43114 (hex 0xa86a). The Fuji testnet chain ID is 43113 (hex 0xa869).

Can I use my existing MetaMask address on Avalanche?

Yes. The Avalanche C-Chain is EVM compatible, so the same 0x address you use on Ethereum works on Avalanche. Adding the network does not create a new account; it just points your wallet at a different chain.

Why do my AVAX not show up in MetaMask?

The two most common reasons: you are on the wrong network (switch to Avalanche C-Chain in the network selector), or your AVAX are on the X-Chain or P-Chain, which MetaMask cannot display. X-Chain and P-Chain funds are visible in the Core wallet and can be moved to the C-Chain from there.

How to Add Avalanche to MetaMask

MetaMask does not include Avalanche by default on a fresh install, but adding it takes under a minute. There are two ways: the built-in network list (fastest) or manual entry (works everywhere, and the only way to add the Fuji testnet).

Method 1: the built-in network list

Open MetaMask and click the network selector in the top left.
Click Add network.
Find Avalanche Network C-Chain in the popular networks list and click Add.
Approve the prompt. MetaMask switches to Avalanche automatically.

That is it. Your existing 0x address works unchanged, because the Avalanche C-Chain is fully EVM compatible.

Method 2: manual settings

If your MetaMask version does not list Avalanche, choose Add a network manually and enter these values exactly:

Network name: Avalanche C-Chain
RPC URL: https://api.avax.network/ext/bc/C/rpc
Chain ID: 43114
Currency symbol: AVAX
Block explorer: https://snowtrace.io

Fuji testnet settings

Developers and testers use Fuji, the Avalanche test network. It must be added manually:

Network name: Avalanche Fuji C-Chain
RPC URL: https://api.avax-test.network/ext/bc/C/rpc
Chain ID: 43113
Currency symbol: AVAX
Block explorer: https://testnet.snowtrace.io

Fuji AVAX has no value and is available for free from the official Avalanche faucet.

Common problems

Balance shows zero: check the network selector first. Tokens live per network, so a wallet that looks empty on Ethereum may hold funds on Avalanche and vice versa.
AVAX sent from an exchange do not appear: some exchanges withdraw to the X-Chain by default. MetaMask only reads the C-Chain. If your withdrawal used an X-avax1... address, import the wallet into Core to move funds across chains, and always choose the C-Chain (0x address) for MetaMask withdrawals.
Wrong chain ID error: double-check you typed 43114, not 43113 (the testnet).

After you connect

Once your wallet is on Avalanche, everything you do (swaps, mints, staking, governance) becomes part of your on-chain history. You can see what that history looks like from the outside with the SOCI4L address lookup, or check the reputation score your activity has earned with the score checker.