Mask: '+int2bin(maskInt)+'
Net: '+int2bin(netInt)+'
Brd: '+int2bin(broadInt);}else{document.getElementById('binarySection').style.display='none';}}
IP Calculator Use
The IP calculator is an essential tool for network administrators, engineers, and students designed to quickly determine the critical boundaries of an IPv4 network. By providing an IP address and a subnet mask (or CIDR prefix), this tool identifies the network address, broadcast address, and the range of usable host addresses available for devices like routers, servers, and PCs.
Subnetting is the process of dividing a larger network into smaller, more manageable sub-networks. This improves security, reduces broadcast traffic, and allows for more efficient use of the limited IPv4 address space.
- IP Address
- The logical address assigned to a device on a network. It consists of 32 bits divided into four 8-bit octets.
- Subnet Mask / CIDR
- The mask defines which portion of the IP address belongs to the network and which portion belongs to the hosts. CIDR (Classless Inter-Domain Routing) is represented by a "/" followed by the number of network bits.
- Network Address
- The first address in the subnet, used to identify the subnet itself. It cannot be assigned to a host.
How It Works
When you perform a calculation using the ip calculator, the system performs bitwise logical operations between the IP address and the subnet mask in binary form. The formulaic approach follows these steps:
Network Address = IP Address AND Subnet Mask
- AND Operation: If both bits are 1, the result is 1. Otherwise, it is 0.
- Broadcast Address: Calculated by taking the Network Address and setting all host bits (the 0s in the mask) to 1.
- Wildcard Mask: The inverse of the Subnet Mask (Mask XOR 255.255.255.255).
- Host Count: Calculated as 2(32 – prefix) – 2 (subtracting 2 for the network and broadcast addresses).
Calculation Example
Example: You have a device with the IP 192.168.10.45 and a subnet mask of 255.255.255.0 (/24). You need to find the network identity and the range of addresses you can assign to other devices.
Step-by-step solution:
- Identify IP in Binary: 11000000.10101000.00001010.00101101
- Identify Mask in Binary: 11111111.11111111.11111111.00000000
- AND them: 11000000.10101000.00001010.00000000 (Result: 192.168.10.0)
- Calculate Hosts: 32 bits – 24 bits = 8 host bits. 28 = 256. 256 – 2 = 254 hosts.
- Result: Network is 192.168.10.0, Usable IPs: 192.168.10.1 to 192.168.10.254.
Common Questions
Why do we subtract 2 from the total hosts?
In standard networking, the first address in a subnet is reserved for the Network Address (identifies the wire) and the last address is the Broadcast Address (sends packets to all hosts). These two addresses cannot be assigned to network interfaces like a laptop or a printer.
What is CIDR notation?
CIDR stands for Classless Inter-Domain Routing. It replaced the old "Classful" system (Class A, B, C) in the 1990s. It uses a slash followed by the number of bits set to 1 in the subnet mask. For example, 255.255.255.0 has 24 bits of "1s" in binary, so it is written as /24.
Can I use an IP address like 127.0.0.1?
While the ip calculator will process 127.0.0.1, this is a reserved loopback address used by your own computer to communicate with itself. It is not routable on the public internet or a local area network.