---
title: "Create a subnet"
description: "Split a custom-range VPC into subnets in MyAccount, so that nodes get their private IPs from the block you choose."
content_type: "how-to"
product: "vpc"
platform: "MyAccount"
url: "/myaccount/vpc/how-to/create-a-subnet/"
topic: ["subnets"]
relationships: {"requires":["/myaccount/vpc/how-to/create-a-vpc/"]}
---

# Create a subnet

A subnet is a smaller block of addresses inside a VPC's range, and the nodes you place in it get
their private IPs from that block.
[VPC address ranges](/myaccount/vpc/concepts/vpc-address-ranges/#planning-subnets) shows how to lay
subnets out.

## Before you begin

- A VPC with a **Custom CIDR** range larger than `/28`, in the **Active** state. That is the kind of
  VPC that takes subnets; to make one, see [Create a VPC](/myaccount/vpc/how-to/create-a-vpc/).
- The block you want: inside the VPC's range, smaller than it, and `/28` or larger. Leave the first
  and last blocks of the range free, because E2E keeps addresses there.
  [VPC address ranges](/myaccount/vpc/concepts/vpc-address-ranges/#planning-subnets) shows which
  blocks work.

## Create the subnet

1. Open **Network > VPC**, open the VPC's actions menu, and choose **Create Subnet**. For a VPC with
   no subnets yet, the link on its **Subnet** tab opens the same form.
2. **Create Subnet** opens with the VPC's name and range at the top. Keep the suggested **Subnet
   Name**, or type one that says what the block is for, such as `web`. The name must not already be
   in use in the region.
3. In **IPv4 Subnet CIDR Block**, enter the block. For a VPC with the range `10.10.0.0/23`,
   `10.10.0.128/25` gives a subnet of 128 addresses. The form shows the block's **IP Size** as you
   type.
4. Click **Create Subnet**.

A message confirms that the subnet was created. A block that overlaps addresses already in use is
refused instead, with "Error while creating subnet, not enough available IPs";
[Troubleshooting VPC](/myaccount/vpc/troubleshooting/vpc/#error-while-creating-subnet-not-enough-available-ips)
shows how to pick one that fits.

## Check the subnet

Select the VPC and open its **Subnet** tab. The new subnet is listed with its **CIDR** and its
**Used/Total IPs**, such as `0/128` for a new `/25`.

Your subnet is ready to use. Pick it under **VPC** when you
[create a node](/myaccount/node/how-to/create-a-node/), or when you
[attach a node to a VPC](/myaccount/node/how-to/attach-a-node-to-a-vpc/), and the node gets its
private IP from the block.