NAT and gateways

Cloud NAT lets instances without external IP addresses reach the internet. It bills for every gigabyte that passes through it, inbound as well as outbound. That is the detail that surprises people: downloads are charged too, and the NAT charge stacks on top of internet egress for outbound traffic.

Billed: Per gibibyte processed through the gateway, in BOTH directions, plus an hourly gateway charge. For Public NAT that charge grows with the number of VMs using it (capped at 32), and each NAT IP address bills hourly; Private NAT gateways bill a flat hourly rate.