One person withdraws ETH over Ethereum mainnet and the fee stings hard. Switch to a network called Arbitrum, same transfer, and the cost drops a long way. In the withdrawal dropdown, names like Arbitrum, Optimism and Polygon look like fresh arrivals you've never heard of. What they actually solve is the old problem of mainnet being too dear.
Here's Layer 2 laid out plainly: why it's both cheap and safe, exactly where it saves against ERC20, what to confirm before you use it, and what it costs to move funds back to mainnet. By the end you'll be able to decide for yourself whether a given withdrawal belongs on L2.
What's in here
What L2 is: Ethereum's cheap lane
L2 is short for Layer 2. Arbitrum, Optimism and Polygon are easiest to picture, roughly, as this: lanes built on top of Ethereum, made to move transfers cheaper and faster.
Here's the comparison. Ethereum mainnet is like a main road through the city center, packed with traffic and expensive to drive on, with everyone crammed onto it. An L2 is like an express flyover built alongside that road: most of the cars drive on the flyover, and once they're through, only the fact that this whole batch made it gets recorded back onto the main road. The main road just signs off on the batch, the actual congestion is diverted onto the flyover, so the cost each car on the flyover carries works out far lower.
This flyover isn't a separate thing built away from Ethereum. Its final ledger and its security still land on Ethereum mainnet. That's the key point, and it's the biggest difference between an L2 and a fully separate, standalone chain.
L2 isn't a different coin, it's Ethereum's cheap fast lane. What you move on it is still ETH, USDC and the like; the road just got cheaper. To understand why mainnet is expensive in the first place, see why ETH withdrawal fees run high: what gas is.
The common L2s, and what each is about
These are the names you're most likely to run into in the dropdown, so here's a quick way to tell them apart:
- Arbitrum: a widely used L2 with a lot of projects in its ecosystem and plenty of wallets and platforms that support it. For everyday dealings with the Ethereum world, it's often the first one people reach for.
- Optimism: another mainstream L2, built on the same idea as Arbitrum (process transactions off-chain first, settle back to mainnet in batches), and the experience is close.
- Polygon: for many people this was their first taste of a "cheap Ethereum." Its positioning is a little different from a pure L2, but to an ordinary user it feels the same: cheaper and faster than mainnet. It's widely supported, and a lot of platforms recognize it.
Exactly how each one works, and whether it counts as a Layer 2 in the strict technical sense, is debated among the technically minded, but that's not your problem when you withdraw. Your problem is the three practical things in the next section.
Why L2 saves without giving up safety
A lot of people flinch at "cheap": is cheap just bad, is it unsafe? With L2, low fees and safety don't pull against each other, and the reason is in the design.
The core of it is one line: do the expensive part off-chain, and write only the cheap part (the result) back to Ethereum. The heavy lifting of ordering and computing transfers happens on the L2's own chain, and Ethereum mainnet doesn't take part directly, so it doesn't tie up that expensive mainnet compute. Once a batch of transactions has piled up, the L2 packs and compresses them and posts a single condensed result back to Ethereum mainnet. Mainnet only pays once for that condensed result, spread across the hundreds or thousands of transactions in the batch, so each one comes out cheap.
On safety, because the final result goes back to Ethereum to be verified and mainnet is the ultimate ledger, an L2 largely inherits Ethereum's security. That's the fundamental difference from a brand-new standalone chain. Of course, "largely" isn't "identical." Each L2 has its own bridge, its own verification mechanism and its own maturity, so strictly speaking the security model isn't exactly the same as mainnet. For everyday small transfers, that gap usually isn't worth much worry; for large amounts or long-term storage, it's worth learning how the specific one you use actually works.
An L2 is cheap because of that "the result gets backed by Ethereum" mechanism. That's a different thing from some fully separate, do-its-own-thing cheap chain. When picking a network, don't act on the words "low fees" alone. First work out whether the receiving side supports that chain and whether the address formats line up. That's what decides whether coins go missing. See the complete guide to picking a Binance withdrawal network.
How much cheaper than mainnet: think orders of magnitude, not exact numbers
Now the question everyone cares about: exactly how much does L2 save versus ERC20 mainnet?
A cold splash first: be suspicious of anyone who writes it as an exact number. Ethereum mainnet gas floats in real time and can multiply several times over when the market runs hot and the chain is congested, and L2 costs move along with mainnet too. So "save $X" or "X times cheaper" can be right today and wrong tomorrow.
But the pattern by order of magnitude is steady, and that's all you need to remember:
| Route | Fee level (relative) | Speed, roughly | When it's worth it |
|---|---|---|---|
| ERC20 (Ethereum mainnet) | High, very high when congested | Depends on how busy mainnet is | When the other end only supports mainnet |
| Arbitrum / Optimism | Clearly below mainnet | Fairly fast | When the other end supports that L2 and you want to save |
| Polygon | Low | Fast | When the other end supports Polygon |
Put another way: for anything in the Ethereum world, take the L2 rather than forcing it onto mainnet, and you usually save a sizable chunk of the fee. How much exactly is whatever Binance's page shows the moment you withdraw and whatever gas the block explorer shows at that time. Those two places are where the real number comes from.
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Three traps to think through first
L2 really does save money, but there are three things that, if you don't work them out in advance, can turn the fee you saved into a much bigger headache.
Trap one: the other end has to support the L2 you pick
This is the number-one trap, and the root of every network-choice problem. To send USDC on Arbitrum into someone's hands, that wallet or exchange has to be able to receive on Arbitrum. If the other end only supports Ethereum mainnet and you take Arbitrum to save money, the coins go out and can't be received. That's not saving money, that's digging yourself a hole.
The order is always: check which networks the other end supports first, then pick the cheapest among those. Go to their deposit page, see which chains it lists for that coin, confirm the L2 you want is there, and only then go ahead.
Trap two: to get funds back to mainnet, you bridge, you wait, you pay again
This one is the easiest to overlook. Say you withdraw ETH to Arbitrum and save on the fee. But if you'll ultimately use that money on Ethereum mainnet (for a mainnet-only app, say), you still have to bridge the asset back from the L2 to mainnet. That step usually goes through an official bridge, which incurs a mainnet gas fee, and some optimistic rollups (Optimism and Arbitrum among them) add a long waiting period to move funds from the L2 back to mainnet (on the order of days, with the exact figure per each project's own terms).
So do the full math. If the money goes into the L2 and gets used on the L2 without coming back to mainnet, the saving is clean. If it has to move back to mainnet sooner or later, add the cost and time of bridging back, and sometimes doing a single mainnet withdrawal is simply less hassle. Where the money ends up being used decides whether L2 is worth it.
Trap three: each L2 is separate, don't cross the addresses
Arbitrum, Optimism and Polygon are all tied to Ethereum, but each is its own network. The same coin on different L2s is a different "version," and the network has to match on both ends when you transfer. Before you withdraw, line up all three: the network you pick, the network the other end supports, and the address format. Making a small test transfer a habit never hurts.
However sure you are, the first time you send to a new address or over a new network, send a few dollars first, wait for it to actually arrive and for the other side to confirm receipt, then send the rest. On-chain transfers are irreversible; there's no undo button. If you've already used the wrong network, start with wrong network, are the funds still there? to judge whether it can be saved.
Who L2 is right for
Bring all of that down to actual people:
- People moving around the Ethereum world a lot who balk at mainnet fees: this is L2's best-fit user. Take the L2 whenever you can; the fees you save add up to real money over a year.
- People whose withdrawal destination is already on an L2: if the wallet, app or platform you're heading to already runs on Arbitrum or Polygon, taking the matching L2 is the obvious call, both cheaper and correct.
- People who just want to move a small amount of USDT to somewhere that supports many networks: you don't have to agonize over L2 here. In this case TRC20 (Tron) is often cheaper and more universal overall, so check the USDT network comparison before deciding. L2 mainly wins when the premise is dealing with the Ethereum world.
- People whose money has to return to Ethereum mainnet sooner or later, and not in large amounts: factor in the fee and wait to bridge back, and sometimes going straight over mainnet is less trouble. L2's saving is best when you aren't bridging back to mainnet often.
In short: L2 isn't a universal money-saving key, it's the cheap lane for when you're dealing with the Ethereum world. Used in the right situation it's great; used in the wrong one, the fee you saved can get eaten back by bridging costs. If you haven't started using Binance yet and want to trim your trading fees along the way, you can enter invite code BNB986 when you sign up for up to 20% off* (whatever Binance's page shows).
Common questions
Are L2 withdrawals really cheaper than Ethereum mainnet?
Most of the time, yes. Arbitrum, Optimism and Polygon run most of the processing off-chain and write only a compressed result back to Ethereum, so a single transfer usually costs far less than ERC20 mainnet. How much you save moves with congestion, and the real figure is whatever Binance's page and the block explorer show the moment you withdraw.
How do you move funds on an L2 back to Ethereum mainnet?
You usually use an official bridge to move the asset from the L2 back to mainnet, which incurs a mainnet gas fee, and some optimistic rollups add a long waiting period. If you'll ultimately use the money on mainnet, add that cost and time in before deciding whether L2 is worth it.
Can I pick Arbitrum or Optimism directly when withdrawing from Binance?
Binance's withdrawal page lists the available networks for each supported coin, and common L2s show up in the dropdown. Whether it's selectable and which ones are listed is whatever you see at the time, and the receiving side has to support the same L2 too.
Is USDC on an L2 the same thing as USDC on mainnet?
It's the same asset, but it exists separately on different networks with different addresses and transfer networks, so you can't just mix sending and receiving across them. The network has to match on both ends, and crossing networks means using a bridge.
L2 is Ethereum's cheap lane. It inherits mainnet's security while cutting costs, and for dealing with the Ethereum world it usually costs a good deal less than ERC20. The conditions: the other end supports that L2, and the addresses line up. If the money has to bridge back to mainnet sooner or later, add that fee and wait into the full math. Fees are always whatever Binance's page and the block explorer show at the time.
Read next
Picking a Binance withdrawal network: which of the five is cheapest Why ETH withdrawal fees run high: what gas is USDT network comparison: cheapest, fastest, safest Use the network picker to choose for youSources: Binance Help Center, ethereum.org Layer 2, Arbiscan, L2BEAT. Fees and waiting periods are live figures, and are whatever each platform and block explorer show at the time.