Keep ETH and POL Ready for Polygon Bridge Transfers

Keep ETH on Ethereum and POL on Polygon PoS before you start a bridge transfer; each network charges gas for the transactions sent on that network. A bridge moves tokens between networks, but it does not make one network’s gas token work on the other. Think of it as paying a separate toll at each end of a road.

Which token pays gas on each side of the bridge?

Ethereum transactions use ETH for gas, while Polygon PoS transactions use POL. This distinction matters because the bridge may ask you to sign more than one transaction. For example, an Ethereum deposit can require a token approval followed by the deposit itself, and both actions need ETH. Polygon PoS has used POL as its native gas token since the MATIC-to-POL change; a wallet may still display the older MATIC symbol.

Token support and contract details can affect which steps appear for a particular asset, so check the Polygon Bridge token and contract checklist before you begin. The gas rule stays the same: the wallet signing a transaction needs the native gas token for that transaction’s network.

How much gas should you keep ready?

There is no fixed amount that covers every transfer. Gas depends on the transaction’s work and current network conditions, and a bridge interaction can cost more than a simple token send. Your wallet estimates the fee before you confirm. Treat that estimate as a guide for the transaction in front of you, not as a universal bridge price.

Before connecting the bridge, check these balances and details:

• For a move from Ethereum to Polygon PoS, keep ETH on Ethereum for any approval and deposit transactions.
• For a move from Polygon PoS to Ethereum, keep POL on Polygon for the withdrawal transaction.
• If you plan to use or send the received tokens, keep the destination network’s gas token there too: POL on Polygon PoS or ETH on Ethereum.
• Leave enough of the transfer asset to bridge after accounting for any approval or bridge requirements shown in the interface.

Why can a withdrawal need gas twice?

A Polygon PoS withdrawal starts with a transaction on Polygon, which uses POL. In the standard PoS bridge flow, the tokens are then withdrawn on Ethereum through a later claim step. That claim is an Ethereum transaction, so it needs ETH in the wallet that submits it. The bridge transfer may be underway even when the claim is not yet ready to submit; the interface should show the next required step.

For a deposit in the other direction, the Ethereum approval and deposit use ETH. Once the tokens arrive on Polygon, spending or forwarding them requires POL. Receiving tokens does not itself mean you have enough gas to move them again.

What should you check before confirming?

Confirm that the wallet is on the intended source network, that the destination address is yours, and that the displayed asset and network match the transfer you want. Keep the needed gas token in that same wallet. If the fee estimate changes while you are preparing the transaction, review the new amount before signing; a transaction can fail or remain pending if its fee settings do not meet network conditions.

The practical habit is simple: prepare gas for every network step, not just the first one. For a Polygon PoS transfer, that usually means POL on Polygon and ETH on Ethereum whenever the flow asks you to submit an Ethereum transaction.