Keep AVAX for the swap fee

Keep some native AVAX in your wallet when you swap tokens on Avalanche, because the network charges transaction fees in AVAX. The amount depends on the work the swap requires and current network conditions. If your wallet holds only the token you want to trade, you may not be able to submit the swap.

Why does a token swap need AVAX?

A swap is a transaction that asks a smart contract—code that runs on the network—to exchange one token for another. The network charges for processing that request, and Avalanche’s documentation says those fees are paid in AVAX. The token you receive cannot usually cover that fee unless it is already AVAX.

A swap can also involve a separate token approval, which gives a contract permission to use a set amount of a token. That approval is its own transaction and may need its own fee. For a look at the available routes, read about Blackhole swap choices on Avalanche. The route can affect what the wallet asks you to sign, so read each prompt.

How much AVAX should you leave in the wallet?

There is no fixed amount that suits every swap. A simple trade and a more involved route can use different amounts of network resources, and fees can change with demand. Use the wallet’s fee estimate as a guide for the transaction in front of you, rather than relying on an old estimate or a general rule.

Before you submit, check the preview for the estimated fee and make sure your available AVAX covers it. Leave a little more than the estimate if you expect to make another transaction soon. That gives you room for a second approval or a follow-up swap without having to top up first.

• Keep AVAX available alongside the token you plan to trade.
• Check whether the wallet requests a separate approval.
• Review the estimated fee again before signing each transaction.
• Keep a reserve if you may need another transaction afterward.

What if the swap fails or the fee looks high?

First check that your wallet is set to the Avalanche network used by the swap, and that it holds AVAX on that network. A balance shown on another network may not pay an Avalanche fee. Then review the fee estimate and the transaction details; a busy network or a more complex route can change the estimate.

If the wallet says there is not enough AVAX, add AVAX to the right network before trying again. If the fee estimate is higher than you want to pay, wait and check later or review the route options. Do not approve a prompt you do not understand, especially if it asks to spend more tokens than you intend.

What is the simplest way to avoid running short?

Keep a small working balance of native AVAX in the same wallet and network as the swap. Check the fee estimate each time, since the cost depends on the transaction. This is more reliable than assuming the swap token will pay the fee or that a previous transaction’s cost will apply again.