Across Bridge fees are easier to understand when you stop looking for one magic number and instead separate the costs behind a transfer on Across Bridge. You are paying to move funds from a source chain to a destination chain, and the total cost usually includes bridge pricing, wallet gas, and sometimes an approval transaction.
That matters because a bridge can look cheap at first glance and still be a poor deal for a tiny transfer. It can also look slightly more expensive than another route while saving you time. Across is an intents-based cross-chain bridge: you deposit on the source chain, a relayer quickly fills the request on the destination chain, and the relayer is later reimbursed after optimistic settlement. That fast fill is the reason transfers can feel quick.
This guide explains what you actually pay, where fees show up, and how to check them before you sign.
Across Bridge is a bridge, not a swap AMM. It is built for cross-chain transfer, not for trading one unrelated token into another. ACX is the Across token, but the cost of a normal bridge transfer comes from the live route, gas, liquidity, and quote shown before confirmation.
The first cost is source-chain gas. This is the network fee your wallet pays to submit the deposit transaction. Ethereum gas may be much higher than gas on L2s like Arbitrum, Optimism, Base, Polygon, or zkSync, but every source chain can become more expensive when demand rises.
The second cost is the bridge quote. This is reflected in the amount you are expected to receive on the destination chain. Across uses relayers with available liquidity to fill user intents quickly. The relayer fronts the destination-side funds, then gets reimbursed later through optimistic settlement. That model is different from a canonical bridge or a lock-and-mint flow where the user may wait through slower settlement rules.
The third cost is token approval, when required. Some tokens need an approval transaction before the bridge transaction. That approval uses source-chain gas, so it can make the first transfer of a token cost more than later transfers.
The fourth cost is destination-chain usability. You may receive the bridged asset, but you still need the destination chain's gas token for your next action. If you bridge into Base, Optimism, Arbitrum, Polygon, or zkSync with no gas there, your funds may arrive but still be awkward to use.
Step 1: Connect your wallet. Open Across Bridge, connect MetaMask or your preferred wallet, and confirm you are using the wallet that holds funds on the source chain.
Step 2: Pick the source and destination chains. Choose where the funds are coming from and where they should land. This is a real money decision, not a display setting.