IP Address Calculator
Our IP Address Calculator helps you calculate subnet masks, network addresses, and IP ranges. Perfect for network administrators, system engineers, and anyone working with IP addressing and subnetting.
Enter CIDR notation (e.g., 24 for /24 or 255.255.255.0)
How to Use This Calculator
Enter an IP address and subnet mask (or CIDR notation like /24), and click "Calculate" to see the network address, broadcast address, usable host range, and total number of hosts. CIDR notation (like 192.168.1.0/24) specifies the subnet mask where the number after the slash represents network bits. Use this for network configuration, IP address planning, subnet design, network troubleshooting, and CIDR notation conversion. Common CIDR values include /24 (255.255.255.0, 254 hosts), /16 (255.255.0.0, 65,534 hosts), and /8 (255.0.0.0, 16.7M hosts).
Why IP Subnetting Matters
Subnetting is essential for efficient network management, security, and IP address allocation. Network administrators use subnetting to divide large networks into smaller, manageable segments, improve security through network isolation, optimize IP address usage, and organize network topology. Understanding subnetting helps you design networks that are secure, efficient, and scalable. Proper subnet design prevents IP address waste, enables network segmentation for security, and simplifies network management. Subnetting is fundamental to network administration, cloud infrastructure, and enterprise networking.
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation uses a slash followed by a number (e.g., /24) to specify the subnet mask. The number represents how many bits are used for the network portion of the IP address, with the remaining bits used for hosts.
How do I calculate the number of usable hosts?
Total hosts = 2^(host bits) - 2. The minus 2 accounts for the network address and broadcast address, which cannot be assigned to hosts. For example, /24 has 8 host bits: 2^8 - 2 = 254 usable hosts.
What's the difference between network and broadcast addresses?
The network address is the first address in a subnet (all host bits are 0) and identifies the subnet. The broadcast address is the last address (all host bits are 1) and is used to send data to all hosts in the subnet. Neither can be assigned to hosts.
Can I use this for IPv6?
This calculator is designed for IPv4 addresses. IPv6 uses a different addressing scheme with 128-bit addresses and different subnetting concepts. Use specialized IPv6 calculators for IPv6 subnetting.