EVM Chain ID List: Ethereum, Base, Arbitrum, Polygon and Every Network You Will Be Asked For

1. What is a chain ID?

Every EVM network, from Ethereum itself to the smallest Layer 2, carries a single integer that tells software which chain it is talking to. That integer is the chain ID. It is not an address, not a contract and not a network name: it is a plain number that nodes, wallets, libraries and dapps all agree on, and it is baked into every transaction you sign.

The number comes from EIP-155, activated in the Spurious Dragon hard fork at block 2,675,000 in 2016. Before it, an Ethereum transaction signed on one chain was valid on any chain where the same account existed, which became a real problem when Ethereum and Ethereum Classic split and shared every address. EIP-155 added the chain ID to the data that gets signed, so the signature only verifies on the chain it was made for.

In practice you meet the chain ID in three places: the network settings of a wallet, the error message of a dapp that does not support the network you are on, and the configuration of any library that signs transactions.

2. Chain ID list: mainnets

The networks below are the ones people search for and the ones this site tracks. Values come from the ethereum-lists/chains registry that chainlist.org and chainid.network are built on, checked on 18 October 2026. Where ChainGate has a gas tracker for the network, the name links to it.

A few of these trip people up. Polygon PoS is 137 and its native token is now POL, not MATIC; Polygon zkEVM is a different chain, 1101. OP Mainnet is the network most people still call Optimism. Arbitrum One (42161) is the main Arbitrum chain; Arbitrum Nova (42170) is a separate one for games and social apps. BNB Smart Chain (56) and opBNB (204) are different networks with the same gas token. Ethereum Classic has network ID 1, the same as Ethereum, but chain ID 61, which is exactly the case EIP-155 was written for.

3. Chain ID list: testnets and local networks

Testnets have their own chain IDs, and a wallet switched to the wrong one will show a zero balance for funds that are perfectly safe on the right one.

The Ethereum testnet statuses are from ethereum.org; Hardhat's default is in its network reference and Geth's in EIP-155 itself. Local chains are the one place where two different tools pick different defaults, so if a wallet complains when you connect to a local node, check whether it is 1337 or 31337.

4. Why does the chain ID matter?

Because it is part of the signature. Under EIP-155 the chain ID is one of the fields hashed before signing, and the signature's v value is set to the chain ID multiplied by two, plus 35 or 36. A node on chain 137 that receives a transaction signed for chain 1 cannot recover a valid sender from it and drops it. The same account, the same nonce and the same recipient exist on both chains, but the signature only works on one.

Everything else follows from that. A wallet uses the chain ID to show the right network name, currency symbol and explorer. A dapp uses it to pick the contract addresses to call, which is why a dapp built for Base refuses to work when your wallet is on Ethereum. A library uses it to build the signature, which is why getting it wrong in configuration produces transactions that never land anywhere.

5. Chain ID vs network ID

Ethereum networks carry two identifiers, and most of the time they are the same number, which is why the terms get mixed up. The Hyperledger Besu documentation puts the difference in one sentence: peer-to-peer communication between nodes uses the network ID, while the transaction signature process uses the chain ID.

The two diverge in a few known cases. Ethereum and Ethereum Classic both have network ID 1, because they were one network until 2016, but chain IDs 1 and 61. Besu's development network uses chain ID 1337 with network ID 2018. For Ethereum mainnet, Sepolia, Hoodi and every Layer 2 in the tables above, the two values match, and nothing you do in a wallet ever asks for the network ID.

Over JSON-RPC they are separate calls: eth_chainId returns the chain ID as a hex string, and net_version returns the network ID as a decimal string. If a tool asks for a "network ID" in a wallet or dapp context, it almost always means the chain ID.

6. How do I find a network's chain ID?

Four ways, from quickest to most authoritative.

The tables on this page

Covers the networks people use day to day, with the hex form next to each number.

chainlist.org or chainid.network

Both read the ethereum-lists/chains registry on GitHub, which lists over 2,800 EVM chains. Searching by name gives the chain ID, the native token and public RPC URLs. MetaMask's own help pages point to Chainlist, with the note that MetaMask does not maintain the data there, so check the entry before adding a network.

The wallet's network settings

MetaMask, Rabby, Trust Wallet and the rest show the chain ID of every configured network under its details. This is the number the wallet is actually signing with.

The RPC endpoint itself

Call eth_chainId on the node. Whatever it returns is, by definition, that network's chain ID, and it is what wallets compare against when you add a custom network:

curl -s -X POST https://mainnet.base.org \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'

# {"jsonrpc":"2.0","id":1,"result":"0x2105"}
# 0x2105 = 8453, so this endpoint is Base

The result is hex. 0x2105 is 8453, so this endpoint belongs to Base. Any JSON-RPC provider answers this call without an API key, which makes it the fastest way to confirm an RPC URL someone handed you is the network they claim.

7. How do I add a network to MetaMask with its chain ID?

Adding a custom network means filling the five fields defined by EIP-3085, the standard behind the wallet_addEthereumChain call that dapps use to do the same thing with one click:

Network name

Free text, for display only.

RPC URL

The JSON-RPC endpoint the wallet will talk to. Public ones are on Chainlist; your own provider's URL works as well.

Chain ID

The number from the tables above. Wallets accept decimal in the form; dapps pass it as 0x-prefixed hex in the API call.

Currency symbol

What the native token is called: ETH on Base and Arbitrum, POL on Polygon, BNB on BNB Smart Chain, AVAX on Avalanche.

Block explorer URL

Optional. Lets the wallet link transactions to the explorer.

The chain ID and the RPC URL have to agree. EIP-3085 requires the wallet to reject the request if the chain ID it was given does not match the value of eth_chainId from the RPC endpoint, and MetaMask shows an error on the form when that happens. If you see it, the number is wrong, the URL is for a different network, or the URL is a dead endpoint; test it with the curl call from the previous section.

8. Why do I get a chain ID mismatch or unsupported chain error?

The wording differs between wallets and dapps, but there are only a handful of causes:

The RPC URL and the chain ID disagree

You typed 8453 but pasted an Ethereum mainnet URL, or the reverse. The wallet asked the endpoint, got a different answer and refused. Fix the one that is wrong.

The dapp does not support the network you are on

"Unsupported chain" or "wrong network" means the dapp's contracts are deployed on other chain IDs. Switch the wallet to one the dapp lists, usually through its own network button.

A transaction was signed for a different chain ID than the node's

The node rejects it with an invalid-sender or invalid-chain-id error, because the EIP-155 signature cannot be recovered on that chain. This is a configuration bug in the sending software, never a network outage.

A local chain changed its ID

Restarting a dev node with a different chain ID than the one MetaMask has saved produces mismatches and stale nonces. Remove and re-add the local network.

Hex and decimal were mixed

0x89 is 137, but a form that expects decimal treats "0x89" as text. Use the decimal form in wallet forms and the hex form in API calls.

9. Decimal, hex and CAIP-2: three ways to write the same ID

Chainlist and wallet forms show chain IDs in decimal. JSON-RPC, EIP-3085 and MetaMask's internal settings use 0x-prefixed hexadecimal, so 137 appears as 0x89, 42161 as 0xa4b1 and 11155111 as 0xaa36a7. They are the same integer; the tables above give both.

Multi-chain tools such as WalletConnect add a third form, CAIP-2, which prefixes the number with a namespace so that chains outside the EVM can share one identifier scheme: Ethereum mainnet is eip155:1, Polygon is eip155:137, Base is eip155:8453. The eip155 part says "this is an EVM chain ID"; the number after the colon is the same chain ID as everywhere else.

10. Do Bitcoin and Solana have chain IDs?

Not in the EIP-155 sense. A chain ID is an EVM concept, and Bitcoin, Litecoin, Dogecoin, Solana and XRP do not have one, which is why a wallet never asks for it when you add those coins.

Those networks tell mainnet and test networks apart in other ways. Bitcoin-family chains use different address formats and network parameters for mainnet and testnet, which is why a testnet address starts differently. Solana runs separate clusters called Mainnet, Devnet and Testnet, each with its own RPC endpoint. If a form asks you for a "chain ID" when depositing Bitcoin or Solana, it is asking which network to use, not for a number.

11. Using chain IDs in code

Any library that signs EVM transactions needs the chain ID, either from configuration or by asking the node. With the ChainGate SDK the hosted networks already carry it, and a custom EVM network takes it as a parameter next to the RPC URL:

import { ChainGate, importWallet } from 'chaingate';

const cg = new ChainGate({ apiKey: process.env.CHAINGATE_API_KEY });
const wallet = importWallet({ phrase: process.env.MNEMONIC });

// Hosted networks already know their chain ID
const base = cg.connect(cg.networks.base, wallet);

// Any other EVM network: pass the RPC URL and the chain ID it reports
const scroll = cg.networks.evmRpc({
  rpcUrl: 'https://rpc.scroll.io',
  chainId: 534352,
  name: 'Scroll',
  symbol: 'ETH',
});
const scr = cg.connect(scroll, wallet);

The value you pass must match what the endpoint reports for eth_chainId, for the reasons in section 4. The tutorial on sending crypto in JavaScript walks through the rest of the flow, and the ChainGate documentation lists the hosted RPC URLs.

12. Where to go from here

With the chain ID settled, the next question on any network is what sending costs there. The multi-chain gas tracker covers every network in the mainnet table above with live fees, and the guide to gas fees explains the numbers it shows. If a transaction has already gone out and you need to find it, the transaction hash guide shows how to look it up on the right explorer. And for wallets, transfers and RPC access across all of these chains from one TypeScript library, ChainGate is the SDK behind this site.

Frequently asked questions