Polygon PoS withdrawal proofs have no fixed gas cost

Submitting a Polygon PoS withdrawal proof to Ethereum has no fixed gas cost; the claimant pays for the contract call at the network price when it is included. The amount depends on the gas the call uses and Ethereum’s fees at that time, not on the value being withdrawn.

A withdrawal starts with a token burn on Polygon, then a separate Ethereum transaction submits proof that the burn is valid. Polygon’s proof-generation API returns the cryptographic payload for that claim; generating it off-chain does not itself incur Ethereum gas. For a closer look at supported assets and contract routes, see this guide to Polygon Bridge token support and contracts.

What does the proof submission pay for?

The claimant pays to have Ethereum execute the bridge contract’s exit call and verify the withdrawal proof. Polygon’s proof-generation API describes the proof as evidence that the burn transaction was included in a Polygon block covered by a checkpoint submitted to Ethereum.

The contract checks that evidence and processes the exit so the corresponding asset can be released on Ethereum. The proof is data carried with the transaction, while the contract’s verification and state updates consume gas. A more involved contract call can use more gas than a basic ETH transfer, as Ethereum.org explains.

Why does the amount change?

Ethereum.org gives the fee calculation as gas used multiplied by the base fee plus the priority fee. Gas used reflects the work required by the transaction; the base fee and tip per unit of gas reflect the price of getting that work included in a block.

That means the same withdrawal can cost different amounts at different times, even if the proof and asset are unchanged. The fee is paid in ETH, and the dollar value also moves with ETH’s market price. Polygon Support says Ethereum network congestion affects the gas fee for completing a withdrawal.

• Proof generation: Polygon’s service prepares the proof payload off-chain.
• Proof submission: The wallet sends the contract call to Ethereum and pays its gas fee in ETH.
• Checkpointing: Polygon validators submit checkpoint data to Ethereum; this network transaction is distinct from an individual user’s claim.

How can a user estimate the cost?

Use the wallet’s estimate for the final Ethereum claim transaction, rather than treating the Polygon burn fee as the total withdrawal cost. The estimate should reflect the contract call and current Ethereum fee conditions; the amount shown can change before the transaction is included.

Check that the wallet has enough ETH on Ethereum to cover the claim, and compare the displayed fee with the value being withdrawn. If the fee is too high, Polygon Support says a user can wait and try the claim later when Ethereum fees are lower. The earlier burn cannot be cancelled, so the next step after waiting is still to submit the proof and pay the Ethereum transaction fee.