IP Subnet Calculator
Calculate subnet information including network address, broadcast address, usable host range, and CIDR notation from IP address and subnet mask.
CIDR Notation
/24
192.168.1.0/24
Network Address
192.168.1.0
Broadcast Address
192.168.1.255
First Usable Host
192.168.1.1
Last Usable Host
192.168.1.254
Usable Hosts
254
Wildcard Mask
0.0.0.255
How to Use This Calculator
- Enter the IP address (e.g., 192.168.1.0).
- Enter the subnet mask (e.g., 255.255.255.0).
- The calculator displays: CIDR notation, network address, broadcast address, usable host range, and more.
- Use this to plan networks, configure routers, or understand IP addressing.
Subnet Calculation Formulas
Subnet information is calculated using bitwise operations:
Broadcast Address = IP Address | ~Subnet Mask
Usable Hosts = 2^(32 - CIDR) - 2
First Host = Network Address + 1
Last Host = Broadcast Address - 1
Example: 192.168.1.0/24 (255.255.255.0): Network = 192.168.1.0, Broadcast = 192.168.1.255, Usable hosts = 254 (192.168.1.1 to 192.168.1.254). For 10.0.0.0/16: Network = 10.0.0.0, Broadcast = 10.0.255.255, Usable hosts = 65,534.
Full Description
IP subnetting is a fundamental networking concept that divides IP networks into smaller, manageable subnets. Subnets improve network organization, security, and routing efficiency. Understanding subnetting is essential for network administrators, system engineers, and anyone working with IP networks.
A subnet mask determines which portion of an IP address is the network ID and which is the host ID. The network address identifies the subnet, the broadcast address is used for network-wide communication, and usable host addresses are assigned to devices. CIDR notation (e.g., /24) provides a compact way to represent subnet masks by indicating the number of network bits.
This calculator helps you determine subnet information from IP addresses and subnet masks. Enter an IP address and subnet mask, and it calculates network address, broadcast address, usable host range, CIDR notation, and more. Use it to plan networks, configure routers, understand IP addressing, or troubleshoot network issues. Subnetting is fundamental to network design and management.
Frequently Asked Questions
What is a subnet?
A subnet is a logical subdivision of an IP network. It divides a network into smaller networks for better organization, security, and routing. Subnets use subnet masks to define which part of an IP address is the network portion and which is the host portion.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents IP addresses and subnet masks in a compact format: IP/prefix_length. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for hosts (256 addresses, 254 usable).
How do I calculate subnet information?
Network address = IP & Subnet Mask. Broadcast address = IP | ~Subnet Mask. Usable hosts = 2^(host_bits) - 2 (subtract network and broadcast). First host = Network + 1. Last host = Broadcast - 1. The calculator does this automatically.
What are common subnet masks?
/24 (255.255.255.0): 256 addresses, 254 usable (common for small networks). /16 (255.255.0.0): 65,536 addresses, 65,534 usable. /8 (255.0.0.0): 16.7M addresses. /32: Single host. /30: 4 addresses, 2 usable (point-to-point links).