Ip Calculator

IP Address Calculator

function calculateIPDetails() { var ipAddressStr = document.getElementById('ipAddress').value.trim(); var cidrPrefixStr = document.getElementById('cidrPrefix').value.trim(); var resultDiv = document.getElementById('result'); resultDiv.innerHTML = "; // Clear previous results // — Input Validation — var ipParts = ipAddressStr.split('.'); if (ipParts.length !== 4) { resultDiv.innerHTML = 'Error: Invalid IP Address format. Must be four octets separated by dots.'; return; } var ipOctets = []; for (var i = 0; i < ipParts.length; i++) { var octet = parseInt(ipParts[i], 10); if (isNaN(octet) || octet 255) { resultDiv.innerHTML = 'Error: Invalid IP Address. Each octet must be between 0 and 255.'; return; } ipOctets.push(octet); } var cidrPrefix = parseInt(cidrPrefixStr, 10); if (isNaN(cidrPrefix) || cidrPrefix 32) { resultDiv.innerHTML = 'Error: Invalid CIDR Prefix. Must be a number between 0 and 32.'; return; } // — IP to 32-bit Integer Conversion — var ipInt = (ipOctets[0] << 24) | (ipOctets[1] << 16) | (ipOctets[2] <>> 0; // Ensure unsigned 32-bit integer // — Subnet Mask Calculation — var subnetMaskInt = (0xFFFFFFFF <>> 0; // — Network Address Calculation — var networkInt = (ipInt & subnetMaskInt) >>> 0; // — Broadcast Address Calculation — var broadcastInt = (networkInt | (~subnetMaskInt)) >>> 0; // — Host Range and Total Hosts Calculation — var firstHostInt, lastHostInt, totalHosts; if (cidrPrefix === 32) { firstHostInt = ipInt; lastHostInt = ipInt; totalHosts = 0; } else if (cidrPrefix === 31) { firstHostInt = networkInt; lastHostInt = broadcastInt; totalHosts = 0; // No usable hosts in a /31 for point-to-point links } else { firstHostInt = networkInt + 1; lastHostInt = broadcastInt – 1; totalHosts = Math.pow(2, (32 – cidrPrefix)) – 2; } // — Integer to Dotted-Decimal IP Conversion Helper — function intToIp(intVal) { return ((intVal >> 24) & 0xFF) + '.' + ((intVal >> 16) & 0xFF) + '.' + ((intVal >> 8) & 0xFF) + '.' + (intVal & 0xFF); } // — Display Results — var subnetMask = intToIp(subnetMaskInt); var networkAddress = intToIp(networkInt); var broadcastAddress = intToIp(broadcastInt); var firstHost = intToIp(firstHostInt); var lastHost = intToIp(lastHostInt); var resultsHtml = '

Calculation Results:

'; resultsHtml += 'IP Address: ' + ipAddressStr + "; resultsHtml += 'CIDR Prefix: /' + cidrPrefix + "; resultsHtml += 'Subnet Mask: ' + subnetMask + "; resultsHtml += 'Network Address: ' + networkAddress + "; resultsHtml += 'Broadcast Address: ' + broadcastAddress + "; if (cidrPrefix < 31) { // Only show host range if there are usable hosts resultsHtml += 'First Usable Host: ' + firstHost + "; resultsHtml += 'Last Usable Host: ' + lastHost + "; resultsHtml += 'Total Usable Hosts: ' + totalHosts.toLocaleString() + "; } else if (cidrPrefix === 31) { resultsHtml += 'Host Range: ' + firstHost + ' – ' + lastHost + ' (Typically used for point-to-point links, no usable hosts for general assignment)'; resultsHtml += 'Total Usable Hosts: 0′; } else if (cidrPrefix === 32) { resultsHtml += 'Host Range: ' + firstHost + ' (Single host address)'; resultsHtml += 'Total Usable Hosts: 0′; } resultDiv.innerHTML = resultsHtml; } .calculator-container { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 8px; padding: 25px; max-width: 500px; margin: 30px auto; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08); } .calculator-container h2 { color: #333; text-align: center; margin-bottom: 25px; font-size: 1.8em; } .calc-input-group { margin-bottom: 18px; } .calc-input-group label { display: block; margin-bottom: 8px; color: #555; font-weight: bold; font-size: 0.95em; } .calc-input-group input[type="text"], .calc-input-group input[type="number"] { width: calc(100% – 20px); padding: 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 1em; box-sizing: border-box; transition: border-color 0.3s ease; } .calc-input-group input[type="text"]:focus, .calc-input-group input[type="number"]:focus { border-color: #007bff; outline: none; box-shadow: 0 0 5px rgba(0, 123, 255, 0.3); } .calc-button { display: block; width: 100%; padding: 12px 20px; background-color: #007bff; color: white; border: none; border-radius: 5px; font-size: 1.1em; font-weight: bold; cursor: pointer; transition: background-color 0.3s ease, transform 0.2s ease; margin-top: 20px; } .calc-button:hover { background-color: #0056b3; transform: translateY(-2px); } .calc-button:active { background-color: #004085; transform: translateY(0); } .calc-result { margin-top: 30px; padding: 20px; background-color: #e9f7ff; border: 1px solid #cce5ff; border-radius: 8px; color: #333; } .calc-result h3 { color: #007bff; margin-top: 0; margin-bottom: 15px; font-size: 1.4em; text-align: center; } .calc-result p { margin-bottom: 10px; line-height: 1.6; font-size: 0.95em; } .calc-result p strong { color: #0056b3; min-width: 150px; display: inline-block; } .calc-result .error { color: #dc3545; font-weight: bold; text-align: center; }

Understanding IP Addresses and Subnetting with an IP Calculator

An IP (Internet Protocol) address is a unique 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. Think of it as a street address for your computer on the internet or a local network.

What is an IP Address?

Most commonly, we encounter IPv4 addresses, which are 32-bit numbers typically expressed in dotted-decimal notation (e.g., 192.168.1.10). This notation divides the 32 bits into four 8-bit sections (octets), with each octet converted to a decimal number from 0 to 255 and separated by dots.

An IP address is logically divided into two parts: the network portion and the host portion. The network portion identifies the specific network on which the device resides, while the host portion identifies the specific device within that network.

What is CIDR?

CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and for IP routing. It was introduced to replace the older classful networking system, which was inefficient in its use of IP address space. CIDR uses a variable-length subnet mask (VLSM) to allow for more flexible and efficient allocation of IP addresses.

A CIDR prefix is denoted by a slash (/) followed by a number (e.g., /24). This number indicates how many bits in the IP address are used for the network portion. The remaining bits are used for the host portion. For example, a /24 prefix means the first 24 bits identify the network, and the last 8 bits identify the host.

Why Use an IP Calculator?

An IP calculator is an essential tool for network administrators, IT professionals, and anyone involved in network design and troubleshooting. It simplifies the complex calculations required to break down an IP address and its associated CIDR prefix into meaningful network parameters. Manually performing these binary calculations can be time-consuming and prone to errors.

Key Outputs of an IP Calculator Explained:

  • IP Address: The specific address you input for a device.
  • CIDR Prefix: The number of bits used for the network portion of the IP address.
  • Subnet Mask: A 32-bit mask used to distinguish the network portion of an IP address from the host portion. It's derived directly from the CIDR prefix. For a /24, the subnet mask is 255.255.255.0.
  • Network Address: The first address in a given network range. It's identified by setting all host bits to zero. This address is used to identify the network itself and cannot be assigned to a host.
  • Broadcast Address: The last address in a given network range. It's identified by setting all host bits to one. Packets sent to this address are delivered to all devices on that specific network segment. This address also cannot be assigned to a host.
  • First Usable Host: The first IP address in the range that can be assigned to a device (e.g., a computer, server, or printer). It's always one greater than the network address.
  • Last Usable Host: The last IP address in the range that can be assigned to a device. It's always one less than the broadcast address.
  • Total Usable Hosts: The total number of IP addresses available for assignment to devices within that specific network segment. This is calculated as 2^(32 - CIDR Prefix) - 2 (subtracting the network and broadcast addresses). For /31 and /32 prefixes, the number of usable hosts is 0 due to their specific use cases (point-to-point links or single host addresses).

Example Usage:

Let's say you have an IP address 192.168.1.10 with a CIDR prefix of /24. Using the calculator:

  • IP Address: 192.168.1.10
  • CIDR Prefix: /24
  • Subnet Mask: 255.255.255.0
  • 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 Usable Hosts: 254

This means that on the 192.168.1.0/24 network, devices can be assigned IP addresses from 192.168.1.1 to 192.168.1.254.

By using this IP calculator, you can quickly and accurately determine these critical network parameters, aiding in efficient network planning and management.

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