azurerm_network_interface cost estimation
A network interface is free. The NIC and its private IP cost nothing. The cost comes from the VM it attaches to, any public IP bound to it, and the traffic it carries.
An azurerm_network_interface (NIC) connects a virtual machine to a subnet and holds its private IP configuration. The NIC itself is free. Azure does not charge for the interface, its private IP address, IP forwarding, or accelerated networking, which is a free feature on supported VM sizes.
The costs associated with a NIC live in the resources bound to it. A public IP attached to the NIC is billed hourly under the current Standard SKU pricing model, whether or not traffic flows. The VM the NIC is attached to is the dominant cost. Any outbound data transfer the VM generates through the NIC is metered per GB once it leaves the region or crosses zones. Attaching multiple NICs to a VM does not add a NIC charge, but it can require a larger VM size, which does cost more.
There is nothing to optimize on the NIC itself. The useful review is what it connects: an idle public IP bound to a NIC is a small recurring charge worth removing, and accelerated networking should be enabled where supported because it is free and improves throughput. c3x prices the VM, any attached public IP, and the traffic the interface carries, and treats the NIC and its private IP as free.
Terraform example
A minimal but realistic configuration that C3X can estimate.
resource "azurerm_resource_group" "main" {
name = "network-rg"
location = "eastus"
}
resource "azurerm_network_interface" "api" {
name = "api-nic"
resource_group_name = azurerm_resource_group.main.name
location = azurerm_resource_group.main.location
ip_configuration {
name = "internal"
subnet_id = azurerm_subnet.app.id
private_ip_address_allocation = "Dynamic"
}
}Pricing dimensions
What you actually pay for when you provision azurerm_network_interface.
| Dimension | Unit | What's being charged |
|---|---|---|
| Network interface | free | The NIC, its private IP, IP forwarding, and accelerated networking have no charge. $0 |
| Attached public IP (optional) | per hour | A Standard public IP bound to the NIC is billed hourly whether or not it carries traffic. ~$0.005/hour per Standard public IP |
| Traffic through the interface | per GB (billed elsewhere) | Outbound and cross-zone data the VM sends through the NIC, metered on the transfer path. |
Optimization tips
Common ways to reduce azurerm_network_interface cost without changing the workload.
Remove idle public IPs bound to NICs
~$3.60/month per public IPA public IP attached to a NIC bills hourly even when the VM is stopped or unused. Detaching public IPs that are not needed removes a recurring charge.
Enable accelerated networking where supported
Accelerated networking is free on supported VM sizes and lowers latency and CPU overhead. There is no reason to leave it off when the size allows it.
Avoid oversizing VMs just for extra NICs
The number of NICs a VM can hold scales with size. Adding NICs is free, but do not jump to a larger, pricier VM size unless the workload truly needs the interfaces.
FAQ
Does an Azure network interface cost money?
No. The NIC and its private IP are free. Cost comes from the VM it attaches to, any public IP bound to it, and the data transfer the VM generates through it.
Is accelerated networking an extra charge?
No. Accelerated networking is a free feature on supported VM sizes. It reduces latency and host CPU usage at no additional cost, so enable it where the VM size allows.
Why is a public IP showing as a cost on my NIC?
Because the public IP itself is billed, not the NIC. Standard public IPs bound to an interface bill hourly regardless of traffic, so an idle one is worth detaching.
Related resources
Estimate this resource in your own Terraform
Free, open source, no API key. C3X parses your Terraform and shows line-item cost for every resource, including azurerm_network_interface.