Mantle Bridge: Plan Deposits, Withdrawals and Gas
A Mantle Bridge transfer uses ETH for Ethereum fees and MNT for Mantle transactions, with a separate Ethereum gas reserve needed to claim withdrawals.
The Aeterna Sol Editors
Two networks set the gas budget for a Mantle Bridge transfer: Ethereum charges ETH, while Mantle charges MNT. You need funds for the chain where each transaction happens, including the final claim when you withdraw to Ethereum.
A transfer through the Mantle Bridge moves an asset between Ethereum and Mantle, rather than swapping it for a different token. The deposit and withdrawal steps are different, so plan for each leg before you send funds.
How do you deposit through Mantle Bridge?
To deposit, choose Ethereum as the source network, Mantle as the destination, and the asset you want to move. For an ERC-20 token such as a stablecoin, you may first need to approve the bridge contract to spend the amount you plan to send.
An approval is its own Ethereum transaction. It allows the transfer to proceed, but it does not move your tokens; you still need to confirm the deposit transaction separately.
Before signing, check the selected token, amount and receiving address. You pay Ethereum gas for any required approval and for the deposit itself. Once the deposit is processed, the corresponding balance appears on Mantle under its mapped token representation.
Keep the transaction record and check the destination balance on Mantle. If it does not appear in your wallet automatically, the balance may still be processing or the wallet may need the correct token information to display it.
What do you need to withdraw to Ethereum?
A withdrawal starts on Mantle and finishes with a claim on Ethereum. First, you send the withdrawal transaction and pay its gas in MNT; once the bridge marks it ready, you switch to Ethereum and submit the claim.
The claim is a separate Ethereum transaction, so you need ETH in the wallet that will claim the funds. Even if you are withdrawing ETH, the balance waiting to be claimed cannot pay the claim’s gas fee.
Check the withdrawal status before treating the transfer as complete. Processing and settlement take time, and the bridge’s status tells you when the claim step is available. Save the transaction details so you can return to the same withdrawal if you close the page.
Deposits and withdrawals are therefore not mirror-image operations. A deposit needs Ethereum gas to start; a withdrawal needs MNT to start on Mantle and ETH to finish on Ethereum.
How much gas should you keep on each network?
Set aside gas for every transaction you expect to sign, not just the transfer amount. The fee is paid in the chain’s native gas token, and the required amount changes with network conditions and transaction complexity.
- For a deposit: Keep ETH on Ethereum for a possible token approval and the deposit.
- For activity on Mantle: Keep native MNT available for transactions after your funds arrive, including any follow-up transfer or swap.
- For a withdrawal: Keep MNT for the withdrawal transaction and ETH on Ethereum for the later claim.
Do not assume that holding a token on one network covers fees on the other. An MNT balance on Ethereum does not pay Mantle transaction fees, and an ETH balance on Mantle does not pay Ethereum gas.
For small transfers, Ethereum fees can take a larger share of the amount than they would for a larger transfer. Check the estimated fees before confirming, and compare them with the amount you expect to receive. If an approval is required, account for it as a separate fee.
What should you check before sending?
Use this sequence to reduce avoidable errors:
- Connect the wallet that holds the asset and confirm the source and destination networks.
- Select the intended token and enter the amount. Check the receiving address and the amount shown for delivery.
- Review any token approval, then sign the deposit or withdrawal transaction.
- For a withdrawal, return to the bridge after processing and submit the Ethereum claim when it is ready.
Be especially careful with token identity. A ticker or familiar name does not prove that two tokens on different networks are the same contract or accepted by the same apps. Confirm the selected asset and destination representation in the bridge before you sign.
The practical rule is simple: budget in two currencies and keep a reserve on both chains when you plan to move funds in both directions. ETH covers Ethereum-side steps, MNT covers Mantle-side steps, and a withdrawal is unfinished until its Ethereum claim has been submitted.