From Bitcoin to Avalanche: The larger value between the following: Three times the bridge toll value of $3 (3 x $3 = $9) OR .00125 BTC.
From Avalanche to Bitcoin: Three times the bridge toll value of $20 combined with the estimated BTC transaction fee (3 x [$20 + est. tx fee]).
For a more in-depth read on how the Avalanche Bridge™ works, please read the following articles.
For any additional questions, please visit our knowledge base or contact a support team member via the chat button at support.avax.network.