Ip Calculator Subnet

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IP Subnet Calculator

e.g., 192.168.1.10
e.g., 255.255.255.0 or /24

Subnet Details:

IP Address:

Subnet Mask:

CIDR Prefix:

Network Address:

Broadcast Address:

First Usable Host:

Last Usable Host:

Total Hosts:

Usable Hosts:

function ipToLong(ipAddress) { var parts = ipAddress.split('.'); if (parts.length !== 4) return NaN; var longIp = 0; for (var i = 0; i < 4; i++) { var octet = parseInt(parts[i], 10); if (isNaN(octet) || octet 255) return NaN; longIp = (longIp <>> 0; // Ensure unsigned 32-bit integer } function longToIp(longIp) { return ((longIp >>> 24) & 0xFF) + '.' + ((longIp >>> 16) & 0xFF) + '.' + ((longIp >>> 8) & 0xFF) + '.' + (longIp & 0xFF); } function subnetMaskToLong(mask) { var longMask; var cidr; if (mask.indexOf('/') !== -1) { cidr = parseInt(mask.substring(mask.indexOf('/') + 1), 10); if (isNaN(cidr) || cidr 32) return { longMask: NaN, cidr: NaN }; longMask = (0xFFFFFFFF <>> 0; } else { longMask = ipToLong(mask); if (isNaN(longMask)) return { longMask: NaN, cidr: NaN }; cidr = longToCidr(longMask); // Validate if it's a valid subnet mask (contiguous ones) if (longMask !== ((0xFFFFFFFF <>> 0)) { return { longMask: NaN, cidr: NaN }; } } return { longMask: longMask, cidr: cidr }; } function longToCidr(longMask) { var cidr = 0; for (var i = 0; i < 32; i++) { if ((longMask << i) & 0x80000000) { cidr++; } else { break; } } return cidr; } function validateIpAddress(ipAddress) { var parts = ipAddress.split('.'); if (parts.length !== 4) return false; for (var i = 0; i < 4; i++) { var octet = parseInt(parts[i], 10); if (isNaN(octet) || octet 255) return false; } return true; } function calculateSubnet() { var ipAddressInput = document.getElementById('ipAddress').value.trim(); var subnetMaskInput = document.getElementById('subnetMask').value.trim(); var resultDiv = document.getElementById('result'); var errorDiv = document.getElementById('error'); errorDiv.style.display = 'none'; resultDiv.style.display = 'none'; // Validate IP Address if (!validateIpAddress(ipAddressInput)) { errorDiv.innerHTML = 'Error: Invalid IP Address format. Please use dotted decimal (e.g., 192.168.1.10).'; errorDiv.style.display = 'block'; return; } var ipLong = ipToLong(ipAddressInput); if (isNaN(ipLong)) { errorDiv.innerHTML = 'Error: Invalid IP Address. Each octet must be between 0 and 255.'; errorDiv.style.display = 'block'; return; } // Validate and convert Subnet Mask var maskData = subnetMaskToLong(subnetMaskInput); var subnetMaskLong = maskData.longMask; var cidrPrefix = maskData.cidr; if (isNaN(subnetMaskLong) || isNaN(cidrPrefix)) { errorDiv.innerHTML = 'Error: Invalid Subnet Mask. Please use dotted decimal (e.g., 255.255.255.0) or CIDR (e.g., /24).'; errorDiv.style.display = 'block'; return; } // Calculations var networkAddressLong = (ipLong & subnetMaskLong) >>> 0; var broadcastAddressLong = (networkAddressLong | (~subnetMaskLong)) >>> 0; var totalHosts = Math.pow(2, (32 – cidrPrefix)); var usableHosts = 0; var firstHostLong = 0; var lastHostLong = 0; if (cidrPrefix 0) ? longToIp(firstHostLong) : 'N/A'; document.getElementById('displayLastHost').innerText = (usableHosts > 0) ? longToIp(lastHostLong) : 'N/A'; document.getElementById('displayTotalHosts').innerText = totalHosts; document.getElementById('displayUsableHosts').innerText = usableHosts; resultDiv.style.display = 'block'; }

Understanding IP Subnetting with the IP Subnet Calculator

IP subnetting is a fundamental concept in computer networking that allows network administrators to divide a large network into smaller, more manageable subnetworks. This process improves network efficiency, enhances security, and optimizes IP address allocation. Our IP Subnet Calculator helps you quickly determine key subnet details for any given IP address and subnet mask.

What is an IP Address?

An Internet Protocol (IP) address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves two main functions: host or network interface identification and location addressing. IP addresses are typically represented in dotted-decimal notation (e.g., 192.168.1.10) for IPv4, consisting of four octets (8-bit numbers) separated by dots, with each octet ranging from 0 to 255.

What is a Subnet Mask?

A subnet mask is a 32-bit number that distinguishes the network portion of an IP address from the host portion. It works by performing a bitwise AND operation with the IP address. The subnet mask can be expressed in two common formats:

  • Dotted Decimal Notation: Similar to an IP address, it's represented as four octets (e.g., 255.255.255.0).
  • CIDR (Classless Inter-Domain Routing) Notation: This is a more concise way to represent the subnet mask by indicating the number of bits used for the network portion (e.g., /24). A /24 mask means the first 24 bits are for the network, and the remaining 8 bits are for hosts.

For example, a subnet mask of 255.255.255.0 is equivalent to /24 in CIDR notation.

Key Subnetting Concepts Explained:

  • Network Address: This is the first address in a subnet. It identifies the network itself and cannot be assigned to a host. All host bits are set to 0.
  • Broadcast Address: This is the last address in a subnet. It is used to send data to all devices within that specific subnet and cannot be assigned to a host. All host bits are set to 1.
  • First Usable Host: The first IP address in a subnet that can be assigned to a device. It is always one greater than the Network Address.
  • Last Usable Host: The last IP address in a subnet that can be assigned to a device. It is always one less than the Broadcast Address.
  • Total Hosts: The total number of IP addresses available within the subnet, including the network and broadcast addresses. Calculated as 2^(32 - CIDR Prefix).
  • Usable Hosts: The number of IP addresses available for assignment to devices within the subnet. This is typically Total Hosts - 2 (subtracting the network and broadcast addresses). For /31 and /32 subnets, the number of usable hosts is 0.
  • CIDR Prefix: The number of bits in the subnet mask that are set to '1', indicating the network portion of the IP address.

How to Use the IP Subnet Calculator:

  1. Enter IP Address: Input the IP address you want to analyze in the "IP Address" field (e.g., 192.168.1.10).
  2. Enter Subnet Mask: Provide the corresponding subnet mask. You can enter it in dotted decimal format (e.g., 255.255.255.0) or CIDR notation (e.g., /24).
  3. Click "Calculate Subnet": The calculator will instantly display the Network Address, Broadcast Address, First Usable Host, Last Usable Host, Total Hosts, and Usable Hosts for your specified subnet.

Example Calculation:

Let's say you have an IP Address of 192.168.1.10 and a Subnet Mask of 255.255.255.0 (or /24).

The calculator would provide the following details:

  • IP Address: 192.168.1.10
  • Subnet Mask: 255.255.255.0
  • CIDR Prefix: /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
  • Total Hosts: 256
  • Usable Hosts: 254

This calculator is an essential tool for network engineers, IT professionals, and students learning about network addressing and subnetting.

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