You can estimate what a cross-chain swap will really cost by checking four parts of the quote, provided you follow the trade from the chain you send from to the chain where you receive funds. The amount shown as “you receive” may already reflect some costs, while others are charged separately.
Keep these points in view as you compare quotes:
- Source-chain gas pays for submitting the transaction.
- Route fees and price impact affect how much value reaches the destination.
- Destination-chain gas may be needed for your next action, even if it is not charged in the swap.
What Will Source-Chain Gas Cost?
Source-chain gas is the network fee for sending the transaction that starts the swap. It is paid to the blockchain’s validators or miners, usually in that chain’s native token, and it can rise when the network is busy.
Check which wallet balance will pay it and whether you have enough of the native token. For example, a wallet holding only an asset you plan to swap may still be unable to start if it has no gas token. The displayed estimate is not a guarantee: the final fee depends on the network and the transaction’s gas use.
A common mistake is to treat gas as part of the swap amount. If you intend to swap $100 worth of a token but need to spend $2 on gas, the trade may begin with less than $100 of value. Check the wallet’s transaction preview and the swap quote separately before confirming.
If the transaction fails after it has been submitted, the network may still charge gas for processing it. That fee does not necessarily mean the swap completed. Check the transaction status on the source chain before trying again, so you do not accidentally submit a duplicate trade.
Which Route Fees Reduce the Amount You Receive?
Route fees are costs associated with the services and liquidity used to move value through a swap. A cross-chain route may involve more than one trade or pool, and each step can affect the final output; the quote should show the estimated amount you will receive after its route costs.
When a trade crosses chains, thor swap can help compare routes between crypto assets, so read the estimated output alongside the route details. The shortest route is not automatically the cheapest: a route with deeper liquidity may offer a better final amount than one with fewer steps. Check the receiving asset and chain as well as the number of steps.
Fees vary by route and market conditions, so there is no single reliable percentage to apply to every trade. Compare the estimated output for the same starting amount and destination asset, and confirm that the quote is still current when you are ready to submit. A quote can change while you review it.
How Much Can Price Impact and Slippage Change the Quote?
Price impact is the change in a pool’s price caused by your trade; it tends to be larger when your trade is big compared with available liquidity. Slippage is the difference between the expected output when you request a trade and the output when it executes, often because prices or liquidity shifted in the meantime.
For example, a quote may show that $100 of a token should return around $98 of another asset. If the pool moves before execution, the actual return may be lower. A slippage tolerance sets how far the result may differ from the expected output before the transaction is rejected; a 1% setting is an illustration, not a recommended setting for every trade.
Look for the quote’s minimum received amount, if shown. This is the least the swap will deliver under its stated conditions. A very loose tolerance can let a trade execute at a worse price; a very tight one can cause it to fail when the market moves slightly. The right setting depends on the asset’s volatility and the route’s liquidity.
Do not confuse a setting with a fee: slippage tolerance does not charge you a percentage by itself. It defines a limit for execution. If a swap fails, source-chain gas may still be spent, so check that limit before signing.
Will You Need Gas on the Destination Chain?
Destination-chain gas is the native token you may need to move or use the asset after it arrives. It is often separate from the swap’s source-chain gas, and a successful swap does not always leave you with enough destination gas for another transaction.
Before swapping, ask what you plan to do next. If you only need to receive and hold the asset, you may not need destination gas immediately. If you intend to send it onward, trade it, or interact with an app, check that you will have the chain’s native token available for that action.
Some routes may account for destination costs in the quote or provide gas as part of the service; others may not. Read the quote details rather than assuming that a displayed output means every later transaction is covered. The thor swap comparison is useful here because the practical choice depends on the full route and what you need to do after arrival.
Before confirming, compare the quote’s received amount, route, slippage limit, and both chains’ gas requirements. For a first swap, a small test amount can show how the process works, though it still incurs transaction costs.
- Keep enough source-chain gas to submit the trade.
- Compare routes by estimated amount received, not step count alone.
- Check slippage limits and destination gas before signing.