I’m not entirely sure and haven’t been able to find that info easily. It was mentioned in the other topic a few times. Like here:
But this is inherently a transaction on L1, so it will be at least the ERC-20 fee, with a little bit on top. I imagine this will be fairly similar to zkSync withdrawals, though numbers I’ve seen quoted so far seem a little bit higher. Of course this is entirely dependent on gas price anyway, so it will fluctuate a lot. I’d say calculate with $50 for now, you can always pop in a better value if you find a good source for it. Of course, you would probably wait for a low fee moment to transfer to L1 anyway as that doesn’t necessarily have to happen right away.
I’m sure there is also some way to automatically retrieve this fee and even automate that part.