Arbitrum, Start Here

Updated 2026-10-29

Short answer: Arbitrum (Arbitrum One) is one of the largest Ethereum layer 2 networks: the same 0x addresses and apps as Ethereum, with much lower fees. Fees are paid in ETH. The ARB token is used to vote on how Arbitrum is run; you don't need it to use the network.

How it relates to Ethereum

Arbitrum handles transactions itself and settles them on Ethereum. ETH on Arbitrum and ETH on Ethereum are separate balances, even with the same address.

Getting on and off Arbitrum

• Many exchanges let you withdraw straight to Arbitrum. Choose Arbitrum One as the network.
• The official bridge back to Ethereum takes about seven days; faster third-party bridges exist, with their own risks. See how crypto bridges work.
• Keep a little ETH on Arbitrum for fees.

Watch out

• Arbitrum One vs Arbitrum Nova: two different networks. Most exchanges and apps use Arbitrum One.
• Fake ARB airdrops and claim sites. Real claims never need your seed phrase or an approval.
• Approvals: how to check and revoke token approvals.

On Crypto Lighthouse

• [Portfolio](/portfolio): your tokens on Arbitrum, DeFi positions and recent activity.
• [Approvals](/rewards): check and revoke, and claim Merkl incentive rewards.
• Token checks and [Check an Address](/check).

Learn more at arbitrum.io.