IP addressing and subnetting are essential concepts in networking. One of the most common questions asked by both beginners and professionals is: how many IP addresses in a /28? Whether you’re managing a home lab, configuring routers, or building enterprise networks, understanding subnet sizes is vital for efficient resource allocation.
A /28 subnet mask is part of Class C addressing and is widely used for creating small networks. It defines how many bits are used for the network portion and how many are left for host devices. Knowing the number of total and usable IP addresses in a /28 network allows you to plan and scale with precision.
In this article, we’ll break down how subnetting works, what a /28 means, how many devices can be supported, and how this subnet compares with others. We’ll also explore how it’s used in real-world IT infrastructure. If you’ve ever wondered how many IP addresses in a /28, this guide will make the concept simple, practical, and actionable.
How many IP addresses in a /28?
A /28 subnet provides 16 total IP addresses, of which 14 are usable for devices. One address is reserved for the network ID and one for the broadcast address, making the rest available for host assignments.
Demystifying /28 Subnets: How It All Adds Up
If you’re wondering how many IP addresses in a /28, you’re not alone—and the answer starts with understanding subnetting. Subnetting is the art of dividing a large IP network into smaller, manageable chunks. In the case of IPv4, every address is 32 bits long. When we talk about a /28 subnet, we’re saying that 28 of those bits are used to define the network, leaving the remaining 4 bits for host addresses.
With 4 bits available, a /28 block contains 16 total IP addresses. But here’s the catch: not all of them can be used for devices. The first IP in the range is reserved as the network identifier, while the last IP is reserved as the broadcast address. That means you’re left with 14 usable IP addresses—just enough for small setups, but not too many to waste space.
This makes /28 subnets perfect for tight, efficient networking—think small teams, cloud instances, or secure internal segments. Whether you’re assigning IPs to routers, workstations, printers, or servers, a /28 gives you just enough room without over-provisioning. It also helps improve network security, control, and resource planning. Mastering this subnet is a key step in becoming confident with IP management.
Calculating How Many IP Addresses in a /28 Network
Total Address Count in a /28 Subnet
To determine how many IP addresses are available in a /28 network, you need to understand how subnetting calculations work. In IPv4, each address is 32 bits long. When you use a /28 subnet, 28 of those bits are allocated for the network portion, leaving the remaining 4 bits for host allocation. This results in 2^4, or 16 total IP addresses within that subnet block.
Usable Host Addresses
Although a /28 subnet contains 16 total addresses, not all of them are available for use by devices. One IP address is reserved as the network identifier, which defines the subnet itself. Another is reserved as the broadcast address, which is used to communicate with all hosts on the network simultaneously. This leaves 14 IP addresses that can be assigned to devices such as computers, printers, phones, or servers.
Example of a /28 Address Range
Consider a /28 network that begins at 192.168.1.0. The full address range spans from 192.168.1.0 to 192.168.1.15. In this example, 192.168.1.0 is the network address, and 192.168.1.15 is the broadcast address. Therefore, the assignable IPs range from 192.168.1.1 to 192.168.1.14, giving exactly 14 usable IPs.
How Network Devices Use the Subnet
Devices such as firewalls, routers, switches, and endpoints are assigned IPs from the usable portion of the /28 range. This structure enables secure and efficient communication across your network while ensuring every device has a unique address. Proper use of a /28 subnet allows for better resource planning and prevents IP conflicts in small network environments.
Top Benefits and Real-World Applications of a /28 Subnet
The /28 subnet is a popular choice in modern networking due to its balance between control, efficiency, and scalability. Here are some of the key scenarios and benefits where a /28 subnet proves especially useful:
- Small Office or Departmental Networks A /28 subnet provides just enough IP addresses—14 usable—to serve a small office or a specific department. It supports essential devices like computers, printers, and phones while keeping network management simple.
- Cloud Infrastructure and Virtual Environments Many cloud platforms allocate /28 IP blocks for deploying virtual machines, containers, or microservices that need dedicated, static IPs. The limited address space enhances performance and reduces security risks in isolated cloud zones.
- Router and Inter-VLAN Segmentation Routers frequently use /28 subnets for connecting different VLANs or setting up point-to-point interfaces. This helps minimize IP address waste and makes routing tables easier to manage.
- Improved Security Through Segmentation Dividing networks into smaller /28 subnets enhances internal security. It limits the spread of malicious traffic and reduces broadcast traffic, helping isolate devices for better protection.
- Efficient IP Address Management With only 16 total IPs (14 usable), a /28 allows precise allocation without over-assigning resources. This is crucial in environments where IPv4 addresses are limited and must be preserved carefully.
Comparing /28 with Other Subnet Sizes
Understanding how many IP addresses in a /28 is useful, but it becomes even more meaningful when compared to other common subnet sizes. Here’s how a /28 stacks up against nearby subnet options:
- /30 Subnet Overview A /30 subnet provides a total of 4 IP addresses, with only 2 usable for devices. One IP is reserved for the network address and another for the broadcast address. This subnet is most commonly used for point-to-point links between two routers where minimal addressing is required.
- /29 Subnet Comparison A /29 subnet contains 8 IP addresses, of which 6 are usable. It’s a practical choice for very small networks, such as a cluster of servers, VoIP systems, or simple isolated environments that require fewer than 7 active devices.
- /28 vs /27 While a /28 subnet offers 16 total IP addresses (14 usable), a /27 doubles the space with 32 total addresses and 30 usable ones. A /27 is a better fit for growing networks where more than 14 devices need IP allocation, offering more room to expand.
- Choosing /28 for Balance and Efficiency The /28 subnet hits a sweet spot between too few and too many addresses. It’s ideal when you need more flexibility than a /29 allows, but don’t want the overhead of a /27. For small offices, development environments, or specific VLANs, /28 offers both structure and scalability.
Real-World Scenarios Using /28 Addressing
Hosting Companies and VPS Providers
In the hosting and virtualization industry, /28 subnets are frequently used to allocate multiple static IP addresses to individual clients. This is especially useful for customers managing server clusters or running multiple virtual machines that each require a dedicated IP. The 14 usable addresses in a /28 block provide enough room for assigning static IPs without wasting resources.
Enterprise Departments
Larger organizations often divide their internal networks by department, and /28 subnets are a perfect fit for this kind of segmentation. IT departments may assign a /28 subnet to a marketing team, HR department, or customer support unit. Devices like VoIP phones, printers, laptops, and desktops can all be managed under this subnet, creating clean, organized internal networking.
Firewall and Gateway Configurations
In network security, /28 subnets play a crucial role in firewall and gateway design. They are commonly used to configure DMZs—also known as demilitarized zones—where public-facing servers such as email, DNS, or web servers are isolated from the internal network. This subnet size is large enough to handle a handful of public services while keeping the attack surface small and manageable.
ISPs and Customer Subnetting
Internet service providers often allocate /28 blocks to small business customers. These clients may need multiple static IPs for hosting mail servers, VPNs, or small web services. The /28 subnet offers a manageable pool of IPs that support business needs without the risk of excessive allocation.
In Summery
Grasping how many IP addresses in a /28 equips IT professionals, students, and engineers with a vital skill in efficient network design. A /28 subnet includes 16 total addresses, with 14 usable for devices—just enough for small-scale environments without wasting valuable IP space. This subnet size is a go-to solution for scenarios like limited cloud deployments, secure departmental segmentation, or small business infrastructures. Its structured approach promotes clarity, security, and ease of scaling. Whether you’re managing a few servers or segmenting a network for better performance, understanding the role of a /28 is foundational. It not only sharpens your subnetting knowledge but also ensures smarter IP allocation in today’s resource-conscious digital landscape.
FAQ’s
How many usable IP addresses are there in a /28 subnet?
A /28 subnet contains 16 total IP addresses, but only 14 of them can be assigned to devices. The remaining two are reserved for network identification and broadcast purposes.
What is the range of a typical /28 subnet?
If the subnet begins at 192.168.1.0, the full range extends to 192.168.1.15. The usable IP addresses are from 192.168.1.1 to 192.168.1.14, excluding the network and broadcast IPs.
Is a /28 subnet suitable for home networks?
Yes, a /28 can be useful for tech-savvy users running multiple virtual machines, servers, or smart devices. While most home routers default to /24, a /28 offers tighter control and segmentation.
Can a /28 subnet be used for public IP assignments?
Absolutely. Hosting companies and ISPs frequently allocate /28 subnets to clients who need multiple static public IPs for web hosting, email servers, or VPNs.
What’s the difference between /28 and /30?
A /28 subnet provides 16 total IPs with 14 usable, while a /30 offers just 4 total and 2 usable. /30 is best for direct links between two network devices like routers.