How to bridge to Base
The routes onto Base, what each one costs, and why getting out again takes seven days.
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There are three ways onto Base and the right one depends on where your funds are now.
From an exchange
Usually the cheapest, and the one most people should use. The exchange moves the funds internally and you pay their withdrawal fee rather than gas on two chains.
Select Base in the network dropdown when you withdraw. That dropdown is the part people miss, and getting it wrong is the most common way funds go astray here. If it rejects your address, the withdrawal error guide explains what the message actually means.
Check the exchange lists Base for the asset you are withdrawing. Support for ETH and USDC is near universal; support for everything else is not.
From Ethereum
The official Base Bridge is the straightforward choice. It charges no protocol fee, so the only cost is Ethereum gas, and it inherits Base's own security rather than introducing a separate set of assumptions. Deposits arrive in minutes.
The live cost table computes what that gas currently comes to.
From another L2
The official bridge does not help here, because it only connects Ethereum and Base. Going through Ethereum means paying Ethereum gas on the way out and again on the way in.
A third-party bridge that routes directly between the two chains avoids that entirely and is normally cheaper even after its own fee. You are trusting that bridge's contracts, which is a real addition to your risk and the reason the official route is worth using when it is available.
Bring ETH
Gas on Base is paid in ETH. Bridge only stablecoins and you will arrive holding something you cannot move, which then requires a second bridging transaction to fix.
It does not take much. At current gas prices a few dollars of ETH covers hundreds of transactions.
Getting out again
Withdrawing from Base to Ethereum through the standard route takes seven days. The withdrawal is started on Base, proven on Ethereum, and finalised only after that challenge window passes.
This is what an optimistic rollup is. The chain assumes its state is valid and leaves a period in which anyone can prove otherwise, and withdrawals cannot settle until that period ends.
Third-party bridges get around it by fronting you the funds on Ethereum immediately and taking the seven-day wait themselves. Their fee is the price of that.
Start small
Send a test amount first, on any route. On Base the fee to do that is a fraction of a cent, so being careful costs almost nothing, and confirming the path works before committing the rest is worth more than the seconds it takes.
Frequently asked
- How long does the official Base bridge take?
- Deposits from Ethereum arrive within minutes. Withdrawals back to Ethereum take seven days, because Base is an optimistic rollup and that window exists for anyone to challenge the state being withdrawn against. The asymmetry is the design working, not a delay anyone can waive.
- Do I need ETH on Base to pay for gas?
- Yes. Gas on Base is paid in ETH and there is no Base token. If you bridge only stablecoins you will arrive with a balance you cannot move, so bring a small amount of ETH alongside. A few dollars covers a long time of ordinary use.
- Is the official bridge cheaper than a third-party one?
- From Ethereum, usually, because it charges no protocol fee. From another L2 it is not an option at all: the official bridge only runs between Ethereum and Base, so routing through Ethereum means paying Ethereum gas twice. A direct third-party bridge is normally cheaper despite its fee.