If you are swapping crypto across chains, keep the fee token for the chain your wallet sends from. You may also need a little native token after the swap, depending on what you plan to do next.
Which chain needs gas first?
Gas is the fee for getting a transaction processed, and each network charges it in its own native token. Ethereum uses ETH; BNB Smart Chain uses BNB; Solana uses SOL. A token balance alone may not cover the fee, even when that token is worth plenty.
For a cross-chain swap, your wallet usually signs a transaction on the source chain to start the move. The bridge then carries the value across chains, and a swap may trade it for the destination asset. If you need to move and swap crypto in one flow, the quickswap swap service is a cross-chain bridge and swap service that handles that task.
The key distinction is who submits each transaction. Your wallet pays gas for transactions it sends; a bridge or relayer may handle destination execution under the route’s design. A relayer is a service that submits a transaction for you. Check the route’s quote to see which costs are included and what token your wallet needs.
How much should I keep aside?
Keep enough native token for the source transaction, plus a small buffer if you might send or swap again after arrival. Fees change with network traffic and the work a transaction does, so there is no reliable fixed amount for every route. Ethereum fees are paid in ETH; Solana fees are paid in SOL, with optional priority fees during busy periods. Ethereum’s gas explanation and Solana’s fee guide describe how these costs are calculated.
For example, say your wallet shows an estimated $3 source fee and you are sending $100 worth of tokens. Treat that $3 as separate from the amount being swapped. If you expect to make another transaction after arrival, also keep enough destination-chain gas for that action; the displayed route estimate may not cover it.
Some chains charge very little for a basic transaction, while others can cost more when demand rises or the transaction is complex. On Solana, creating a token account can add a deposit-like cost called rent. That is separate from the ordinary transaction fee, so a first-time token receipt can need more SOL than a later one.
What should I check before signing?
Look at the fee estimate and token symbol in your wallet before you approve the source transaction. Make sure the wallet is on the intended source network and has enough of that network’s native token. If the estimate changes sharply, pause and check again; congestion can raise fees, and a failed Ethereum transaction can still consume gas.
Also decide what you will do with the destination asset. If you only need to receive it, you may not need destination gas immediately when the route covers delivery. If you plan to trade, send, or use it in an app, leave some native token there or arrange to get it separately. For that one-flow move and trade, quickswap gives you a way to bridge and swap crypto across chains.
Common questions
Can I pay gas with the token I am swapping?
Usually, no. The transaction fee is charged in the chain’s native token, not automatically deducted from the asset you are swapping. For example, holding a stablecoin on Ethereum does not by itself pay an Ethereum gas fee; your wallet needs ETH, unless the route specifically covers that fee.
Do I need gas on both chains?
You need gas on the source chain for any transaction your wallet sends there. Destination gas depends on how the route works and what you do after arrival. A relayer may submit the destination step, while a later transfer or app action from your wallet will generally need the destination chain’s native token.
Before acting, ask yourself: have I kept enough of the right native token for the transaction I intend to make next?
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