google_compute_router cost estimation

A google_compute_router is a regional Cloud Router that speaks BGP to exchange dynamic routes between a VPC and peer networks reached over Cloud VPN, Cloud Interconnect, or Network Connectivity Center. The router itself is free. Running BGP sessions, advertising routes, and learning routes carry no charge.

The router is where two paid things get attached, which is why it shows up in cost conversations. First, Cloud NAT: a NAT configuration (google_compute_router_nat) lives on a Cloud Router and bills per gateway-hour plus per-GB data processed. The router is free, but the NAT config on it is not. Second, hybrid connectivity: the VPN tunnels and Interconnect VLAN attachments whose routes the router advertises have their own hourly and per-GB charges, and the egress that flows across them bills per GB.

So a Cloud Router with no NAT and no attachments is genuinely free. The moment it hosts a NAT gateway or anchors a VPN or Interconnect, the cost is on those components. c3x prices the Cloud NAT config, VPN tunnels, and Interconnect attachments a router carries and treats the router and its BGP sessions as the free control plane they are.

Terraform example

A minimal but realistic configuration that C3X can estimate.

resource "google_compute_router" "main" {
  name    = "main-router"
  region  = "us-central1"
  network = google_compute_network.main.id

  bgp {
    asn = 64514
  }
}

Pricing dimensions

What you actually pay for when you provision google_compute_router.

Dimension	Unit	What's being charged
Cloud Router and BGP	free	The router, its BGP sessions, and route advertisement have no charge. $0
Cloud NAT hosted on the router	per hour + per GB	A google_compute_router_nat config attached to the router bills per gateway-hour plus per-GB data processed. ~$0.044/gateway-hour + $0.045/GB
VPN / Interconnect attachments	per hour + per GB	Hybrid connectivity whose routes the router advertises, billed per tunnel or attachment plus egress. Cloud VPN: ~$0.05/tunnel-hour + egress

Optimization tips

Common ways to reduce google_compute_router cost without changing the workload.

One Cloud Router per region for NAT

A single Cloud Router can host the NAT config for all subnets in its region. Extra routers add operational surface without reducing the NAT charge, which is driven by gateway-hours and data.

Tune NAT port allocation, not the router

The router is free; NAT cost is the lever. Right-sizing minimum ports per VM and enabling dynamic port allocation avoids over-provisioning NAT gateway capacity.

Consolidate hybrid connectivity

VPN tunnels and Interconnect attachments each bill hourly. Advertising routes for several networks through shared connectivity avoids duplicate tunnel charges.

FAQ

Does a Cloud Router cost money?

No. The Cloud Router and its BGP sessions are free. Cost comes from what you attach to it: a Cloud NAT configuration, or the VPN tunnels and Interconnect attachments whose routes it advertises.

Why do I need a Cloud Router if it is free?

Cloud NAT and dynamic routing over VPN or Interconnect require a Cloud Router to host the config and run BGP. It is a free prerequisite whose attached components carry the charge.

How do I estimate the cost around a Cloud Router?

Price the Cloud NAT config and any VPN or Interconnect attachments on it, plus their egress. c3x prices those components and treats the router itself as free.