The short answer

A layer 2 executes your transaction off the base chain and posts data back to it, which is why it is cheaper. You still pay in ETH on the major Ethereum layer 2s, but it must be ETH on that layer 2. Transfers within the layer 2 are fast; canonical withdrawals back to the base chain are slow. And token versions can differ between the two.

What a layer 2 actually does

A layer 2 processes transactions on its own network and publishes data to a base chain, usually Ethereum, so that the base chain can be used to verify or dispute what happened. You get much cheaper execution while still anchoring to Ethereum.

The cost structure follows directly. OP Mainnet documents its fee as an execution fee, an L1 data fee and an operator fee. Base documents an execution cost plus an L1 security cost. In both cases, part of what you pay is the cost of writing to Ethereum, which is why a layer 2 fee can rise while the layer 2 itself is quiet.

The gas trap

Ethereum’s major layer 2s use ETH for gas, which sounds convenient and causes a specific mistake: people fund the wrong chain. ETH on Ethereum mainnet cannot pay for a transaction on Base, Arbitrum One or OP Mainnet. It has to be ETH on that network.

An account holding stablecoins on a layer 2 and ETH on mainnet can receive on the layer 2 but not send from it. The fix is to move a small amount of ETH onto the layer 2, by bridging or by withdrawing from an exchange directly to that network.

Networks with their own gas asset, such as Polygon PoS with POL, make this more obvious but no less common.

Going back is not like coming in

Depositing to a layer 2 is usually quick. Withdrawing through the canonical bridge on an optimistic rollup involves a challenge period of several days. This asymmetry surprises people who assume a round trip takes twice the one-way time.

If you need funds on mainnet quickly, plan another route: a third-party bridge that fronts liquidity, or an exchange that accepts deposits on the layer 2 and lets you withdraw on Ethereum. Both cost more than waiting.

Token versions differ by layer

Because layer 2s existed before issuers deployed natively on them, several carry both a bridged representation and a native token for the same asset. Arbitrum One is the clearest case, with native USDC alongside bridged USDC.e.

On the base chain this is rarely an issue, since that is usually where the native token originates. On a layer 2, check which version you hold before a deposit or a swap.

When to use which

Use a layer 2 when the recipient accepts it and the amount is modest: the fee saving is large and the settlement guarantees are good enough for an ordinary transfer. Use the base chain when it is the only network accepted, when the counterparty requires it, or when the amount is large enough that fees are immaterial and you prefer base-layer settlement.

As always, acceptance decides first. A layer 2 that your destination does not list is not an option at any price.

Frequently asked

Do I need a special token for gas on a layer 2?

On the major Ethereum layer 2s, no: they use ETH. But it must be ETH held on that layer 2, not on Ethereum mainnet. Networks like Polygon PoS use their own asset instead.

Why did my layer 2 fee go up when the network was quiet?

Part of a layer 2 fee covers posting data to Ethereum, so it rises with Ethereum congestion regardless of local activity.

Is a layer 2 transfer as secure as a mainnet one?

They have different security models. For an ordinary transfer between two parties, layer 2s are widely used and behave predictably. The meaningful differences appear in withdrawal timing and in what you are trusting during a bridge.

Can I send directly from one layer 2 to another?

Not natively. It requires a bridge or an intermediary such as an exchange, with the same checks as any other cross-network move.

Before you act

  • Hold the gas asset on the network you are sending from, not a different one.
  • Confirm the recipient accepts that specific layer 2.
  • Plan for a slow canonical withdrawal if you need funds back on mainnet.
  • Check which token version you hold on the layer 2.
PUT IT TO USEWork out a gas scenario

Sources & further reading

  1. Optimism: transaction fees

    Execution, L1 data and operator fee components.

  2. Base: network fees

    L2 execution cost and the L1 security component.

  3. Arbitrum: gas and fees

    Gas estimates that can already include the parent-chain cost.

  4. Ethereum: bridges

    Moving between layers and the assumptions involved.

Sources checked on 18 September 2026. Network features and platform support can change; check the relevant provider before acting.

AI-assisted editorial content; no independent expert review or transaction verification is claimed. Tokens and bridges carry issuer, market and smart-contract risks. This is educational information, not investment advice. Read our editorial policy.