IPv4 Subnet Calculator
/32 (255.255.255.255)
/31 (255.255.255.254)
/30 (255.255.255.252)
/29 (255.255.255.248)
/28 (255.255.255.240)
/27 (255.255.255.224)
/26 (255.255.255.192)
/25 (255.255.255.128)
/24 (255.255.255.0)
/23 (255.255.254.0)
/22 (255.255.252.0)
/21 (255.255.248.0)
/20 (255.255.240.0)
/19 (255.255.224.0)
/18 (255.255.192.0)
/17 (255.255.128.0)
/16 (255.255.0.0)
/15 (255.254.0.0)
/14 (255.252.0.0)
/13 (255.248.0.0)
/12 (255.240.0.0)
/11 (255.224.0.0)
/10 (255.192.0.0)
/9 (255.128.0.0)
/8 (255.0.0.0)
Calculation Results
Network Address:
Usable Host Range:
Broadcast Address:
Total Number of Hosts:
Usable Number of Hosts:
Subnet Mask:
Wildcard Mask:
CIDR Notation:
What is a Subnet Calculator?
A Subnet Calculator is an essential tool for network engineers and IT professionals to manage and divide IP address spaces efficiently. Subnetting allows you to break down a single large network into smaller, more manageable sub-networks (subnets). This process improves network security, reduces congestion by limiting broadcast traffic, and helps in the organized allocation of IP addresses.
How Subnetting Works
In the IPv4 protocol, an address consists of 32 bits, divided into a network portion and a host portion. The Subnet Mask determines where the network portion ends and the host portion begins. By increasing the number of bits used for the network (using CIDR notation), you create more subnets but fewer hosts per subnet.
Practical Example:
If you have an IP of 192.168.1.0 with a /24 mask (255.255.255.0):
If you have an IP of 192.168.1.0 with a /24 mask (255.255.255.0):
- Network ID: 192.168.1.0
- First Usable Host: 192.168.1.1
- Last Usable Host: 192.168.1.254
- Broadcast Address: 192.168.1.255
- Total Usable Hosts: 254
Key Terms to Know
- CIDR (Classless Inter-Domain Routing): A method for allocating IP addresses and IP routing. It is denoted by a slash followed by a number (e.g., /24).
- Network Address: The first address in the subnet, used to identify the network itself. It cannot be assigned to a device.
- Broadcast Address: The last address in the subnet, used to send data to all devices on that network.
- Usable IP Range: The specific set of addresses that can be manually or dynamically (via DHCP) assigned to devices like PCs, servers, and routers.
- Wildcard Mask: Used primarily in Access Control Lists (ACLs) and OSPF routing, it is the inverse of the subnet mask.
Why Subnetting is Crucial for SEO & Network Performance
While subnetting is a technical networking concept, it plays a role in organizational efficiency. Proper IP planning prevents IP conflicts and downtime, ensuring that web servers and internal resources remain accessible. For businesses with multiple departments, subnetting provides logical isolation, preventing a security breach in one segment from easily spreading to another.