Internet and inter-region egress

This is data your workload sends out of Google Cloud to the public internet. It is billed per gibibyte, at a rate that depends on where the traffic is going, and it appears as a separate SKU for every source-to-destination lane. Standard inbound data transfer is generally free, though processing charges such as Cloud NAT or load balancer data processing can still apply to it.

Billed: Per gibibyte leaving Google Cloud to the internet. Premium Tier is priced by source and destination and tiered by monthly volume, counted per SKU across the billing account; Standard Tier by source region. Standard inbound data transfer is generally free.

This is traffic between two Google Cloud regions: it never leaves Google, but it is still billed. The rate depends on where the source and destination regions are, and intercontinental pairs cost several times what two regions on the same continent do. It is the usual hidden cost of a multi-region architecture.

Billed: Per gibibyte moved between two Google Cloud regions, priced by the source and destination area (North America, Europe, Asia and so on).

Traffic between zones inside the same region. The per-gigabyte rate is low enough to look negligible and high enough to matter at volume, which is why it tends to show up as an unexplained line rather than as something anyone chose.

Billed: Per gibibyte crossing zones within one region, charged to the project of the sending VM. Small per gigabyte, very large in aggregate for chatty systems.