Arbitrum is a layer 2 network built on top of Ethereum. It processes transactions on its own chain and then posts compressed data about them back to Ethereum. The result: Ethereum-style apps and addresses, with much lower fees and faster confirmations.
How Arbitrum works
Arbitrum One — the main Arbitrum network — is an optimistic rollup. "Rollup" means it bundles many transactions together and publishes their data to Ethereum. "Optimistic" means those batches are assumed to be valid unless someone proves otherwise within a challenge window. Because the data lives on Ethereum, anyone can reconstruct Arbitrum's state and check it.
The network is developed by Offchain Labs and governed by the Arbitrum DAO, whose governance token is ARB. You do not need ARB to use the network: fees are paid in ETH.
Why fees are lower
Instead of every transaction competing for space in an Ethereum block, Arbitrum processes them on its own chain and shares the cost of posting data to Ethereum across many users. Simple transfers on Arbitrum typically cost a small fraction of the equivalent on Ethereum mainnet.
Same address, different network
Arbitrum uses the same address format as Ethereum (0x…), so the same wallet address works on both. That is convenient, but it is also the most common source of confusion: the balance on Ethereum and the balance on Arbitrum are separate. ETH sent on Arbitrum does not appear on Ethereum, and vice versa. In your wallet, switch to the Arbitrum One network (chain ID 42161) to see Arbitrum balances.
Tokens on Arbitrum
- ETH — the gas token, used to pay fees.
- USDC — issued natively by Circle on Arbitrum.
- USDT — also available on Arbitrum.
Token contract addresses on Arbitrum differ from their Ethereum counterparts, so always check you are using the right token when you add it to a wallet.
Moving funds to and from Arbitrum
There are three common routes:
- Exchange withdrawal: many exchanges let you withdraw directly on Arbitrum. Choose "Arbitrum One" as the network.
- The official bridge: deposits from Ethereum usually arrive within minutes. Withdrawals back to Ethereum through the native bridge are subject to the challenge period of roughly a week.
- A swap service: send the asset on one network and receive it on another, e.g. ETH on Base or ETH on Ethereum, without waiting for the bridge's withdrawal window.
Is Arbitrum safe?
Arbitrum is one of the most widely used Ethereum layer 2s and inherits much of its security from Ethereum, since its data is published there. Like every layer 2, it still has its own components — such as the sequencer that orders transactions and the upgradeable contracts — which carry risks that Ethereum mainnet does not. Independent trackers such as L2BEAT document each rollup's current risk profile in detail.
Arbitrum checklist before you send
- Confirm the receiver supports Arbitrum One, not just "Ethereum".
- Keep a little ETH on Arbitrum for fees.
- Double-check the network selected in your wallet or exchange withdrawal screen.
Related reading: BEP20 vs ERC20, how to convert ETH to BTC.
What can you do on Arbitrum?
Arbitrum supports the same smart contracts as Ethereum, so most popular Ethereum apps — decentralised exchanges, lending protocols, NFT marketplaces and payment tools — run there too. For everyday users, the main appeal is simple: the same ETH, USDC and USDT, with transfers that cost little and confirm within seconds. Many centralised exchanges also support Arbitrum deposits and withdrawals, which makes it a convenient route on and off Ethereum's ecosystem.
Arbitrum One vs Arbitrum Nova
There is more than one Arbitrum chain. Arbitrum One is the main general-purpose rollup and the one most wallets, exchanges and apps mean when they say "Arbitrum". Arbitrum Nova is a separate chain designed for very low-cost, high-volume applications such as games and social apps, using a different data-availability model. Funds on Nova are not visible on Arbitrum One and vice versa, so always check which one a service supports.
Explorer and wallet settings
Arbitrum One transactions can be tracked on Arbiscan. Most wallets, including MetaMask, offer Arbitrum One as a built-in network; if not, add it from the official Arbitrum documentation rather than from an unknown website, so the RPC endpoint and chain ID are correct.
Frequently asked questions
Do I need the ARB token to use Arbitrum?
No. Fees on Arbitrum One are paid in ETH. ARB is the governance token of the Arbitrum DAO.
Is my Ethereum address the same on Arbitrum?
Yes, the address is the same, but the balances are separate. Switch your wallet to Arbitrum One to see them.
How long do withdrawals from Arbitrum to Ethereum take?
Through the official bridge, roughly a week because of the challenge period. Exchanges and swap services can be faster.
What happens if I send ETH on Arbitrum to an exchange that only supports Ethereum?
The exchange may not credit it automatically. Contact its support with the transaction hash; recovery is not always possible.