Practical guide
Estimate GCP network egress by destination
A practical GCP egress forecast separates traffic that stays local from inter-region, internet, and service-specific transfer charges.
Updated · Sources checked
Destination determines the question
Google Cloud networking distinguishes traffic within a zone or region, between regions, through Interconnect, and to the internet. The source service can also have its own pricing rules. Do not use one generic egress rate for every byte.
For a rate-free example, split 20 TiB of monthly outbound traffic into 12 TiB to internet clients, 5 TiB to another region, and 3 TiB within the applicable local boundary. Multiply each bucket by its documented destination rate; the final cost is their sum. If a CDN serves 8 TiB of the internet responses, price that under CDN rules rather than count it twice as direct VM egress.
Use flow logs, load-balancer metrics, service billing exports, and deployment topology to identify source and destination. Then test practical changes: co-locate services, cache content, or use private connectivity where technically justified. A lower bill is not useful if it breaks latency, resilience, or data-residency requirements.
Use the GCP Network Egress Calculator only for Standard Tier internet transfer out from Iowa. Pair it with source-service pricing when the path is regional, Interconnect, Premium Tier, or adds processing charges.
FAQ
Is inbound internet traffic billed the same way?
No. Check the source service’s pricing rules; outbound destination is the central egress variable.
Is same-region traffic always free?
Not universally. Confirm the exact service and network path in Google’s documentation.