Ip Address Range Calculator

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IP Address Range Calculator

e.g., 192.168.1.100
e.g., 255.255.255.0 or /24

Calculation Results:

Network Address:

Broadcast Address:

First Usable IP:

Last Usable IP:

Total Addresses:

Usable Hosts:

CIDR Prefix:

Subnet Mask:

Error:
function parseIpAddress(ipString) { var parts = ipString.split('.'); if (parts.length !== 4) { throw new Error("Invalid IP address format. Must have 4 octets."); } var ipInt = 0; for (var i = 0; i < 4; i++) { var octet = parseInt(parts[i], 10); if (isNaN(octet) || octet 255) { throw new Error("Invalid IP address octet: " + parts[i] + ". Must be between 0 and 255."); } ipInt = (ipInt <>> 0; // Ensure unsigned 32-bit integer } function cidrToMaskInt(cidr) { if (cidr 32) { throw new Error("CIDR prefix must be between 0 and 32."); } if (cidr === 0) return 0; return (-1 <>> 0; // Generate mask and ensure unsigned 32-bit } function parseSubnetMask(maskString) { var cidr = 0; var maskInt = 0; if (maskString.indexOf('/') === 0) { // CIDR format cidr = parseInt(maskString.substring(1), 10); if (isNaN(cidr)) { throw new Error("Invalid CIDR prefix. Must be a number."); } maskInt = cidrToMaskInt(cidr); } else { // Dotted decimal format var parts = maskString.split('.'); if (parts.length !== 4) { throw new Error("Invalid subnet mask format. Must have 4 octets or be a CIDR prefix."); } for (var i = 0; i < 4; i++) { var octet = parseInt(parts[i], 10); if (isNaN(octet) || octet 255) { throw new Error("Invalid subnet mask octet: " + parts[i] + ". Must be between 0 and 255."); } maskInt = (maskInt <>> 0).toString(2); // Pad with leading zeros if necessary for full 32 bits while (binaryMask.length < 32) { binaryMask = '0' + binaryMask; } if (binaryMask.indexOf('01') !== -1) { throw new Error("Invalid subnet mask format. Bits must be contiguous ones followed by contiguous zeros."); } // Calculate CIDR from maskInt var tempMask = maskInt; while ((tempMask & 1) === 0 && cidr >>= 1; cidr++; } cidr = 32 – cidr; } return { cidr: cidr, maskInt: maskInt }; } function intToDotted(ipInt) { return ((ipInt >>> 24) & 0xFF) + '.' + ((ipInt >>> 16) & 0xFF) + '.' + ((ipInt >>> 8) & 0xFF) + '.' + (ipInt & 0xFF); } function calculateIPRange() { var ipAddressInput = document.getElementById("ipAddress").value.trim(); var subnetMaskInput = document.getElementById("subnetMask").value.trim(); var resultDiv = document.getElementById("result"); var errorDiv = document.getElementById("error"); var errorMessageSpan = document.getElementById("errorMessage"); resultDiv.style.display = 'none'; errorDiv.style.display = 'none'; errorMessageSpan.textContent = "; try { var ipAddressInt = parseIpAddress(ipAddressInput); var maskInfo = parseSubnetMask(subnetMaskInput); var subnetMaskInt = maskInfo.maskInt; var cidrPrefix = maskInfo.cidr; var networkAddressInt = ipAddressInt & subnetMaskInt; var broadcastAddressInt = networkAddressInt | (0xFFFFFFFF ^ subnetMaskInt); // Using XOR with all ones for bitwise NOT var firstUsableInt = networkAddressInt + 1; var lastUsableInt = broadcastAddressInt – 1; var totalAddresses = Math.pow(2, 32 – cidrPrefix); var usableHosts = Math.max(0, totalAddresses – 2); // Subtract network and broadcast addresses document.getElementById("networkAddress").textContent = intToDotted(networkAddressInt); document.getElementById("broadcastAddress").textContent = intToDotted(broadcastAddressInt); if (usableHosts > 0) { document.getElementById("firstUsableIP").textContent = intToDotted(firstUsableInt); document.getElementById("lastUsableIP").textContent = intToDotted(lastUsableInt); } else { document.getElementById("firstUsableIP").textContent = "N/A (No usable hosts)"; document.getElementById("lastUsableIP").textContent = "N/A (No usable hosts)"; } document.getElementById("totalAddresses").textContent = totalAddresses; document.getElementById("usableHosts").textContent = usableHosts; document.getElementById("cidrPrefix").textContent = "/" + cidrPrefix; document.getElementById("calculatedSubnetMask").textContent = intToDotted(subnetMaskInt); resultDiv.style.display = 'block'; } catch (e) { errorMessageSpan.textContent = e.message; errorDiv.style.display = 'block'; } }

Understanding the IP Address Range Calculator

An IP Address Range Calculator is an essential tool for network administrators, IT professionals, and anyone involved in network planning and management. It helps you determine the various components of an IP network given an IP address and its corresponding subnet mask or CIDR prefix.

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. In IPv4, IP addresses are 32-bit numbers, typically represented in dotted-decimal notation (e.g., 192.168.1.100).

What is a Subnet Mask?

A subnet mask is a 32-bit number that separates the IP address into two parts: the network address and the host address. It works by masking a portion of the IP address to identify the network. Like IP addresses, subnet masks are often written in dotted-decimal notation (e.g., 255.255.255.0).

What is CIDR?

CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and routing IP packets. It was introduced to replace the old classful network addressing system. CIDR notation simplifies the representation of a subnet mask by appending a slash (/) and the number of network bits (the CIDR prefix) to the IP address (e.g., 192.168.1.0/24). A /24 prefix means the first 24 bits are for the network, and the remaining 8 bits are for hosts.

Key Terms Explained by the Calculator:

  • Network Address: This is the first address in a given network range. It identifies the network itself and cannot be assigned to a host. All devices on the same network share the same network address.
  • Broadcast Address: This is the last address in a given network range. Packets sent to this address are delivered to all hosts on that network. It also cannot be assigned to a host.
  • First Usable IP: This is the first IP address in the range that can be assigned to a host device (e.g., a computer, server, or printer). It is always one greater than the Network Address.
  • Last Usable IP: This is the last IP address in the range that can be assigned to a host device. It is always one less than the Broadcast Address.
  • Total Addresses: The total number of IP addresses available within the defined network range, including the network and broadcast addresses.
  • Usable Hosts: The total number of IP addresses that can actually be assigned to devices within the network. This is always Total Addresses - 2 (subtracting the network and broadcast addresses). For very small subnets like /31 or /32, this can be 0 or 1.

How to Use the Calculator:

  1. Enter an IP Address: Input any valid IPv4 address (e.g., 192.168.1.100). This IP address will be used to determine which network it belongs to based on the subnet mask.
  2. Enter a Subnet Mask or CIDR Prefix: You can either enter the subnet mask in dotted-decimal format (e.g., 255.255.255.0) or use CIDR notation (e.g., /24).
  3. Click "Calculate IP Range": The calculator will instantly display the Network Address, Broadcast Address, First Usable IP, Last Usable IP, Total Addresses, Usable Hosts, CIDR Prefix, and the calculated Subnet Mask.

Example:

Let's say you have an IP address 172.16.50.75 and a subnet mask of 255.255.255.192 (which is /26 in CIDR notation).

  • IP Address: 172.16.50.75
  • Subnet Mask: 255.255.255.192 (or /26)

The calculator would yield the following results:

  • Network Address: 172.16.50.64
  • Broadcast Address: 172.16.50.127
  • First Usable IP: 172.16.50.65
  • Last Usable IP: 172.16.50.126
  • Total Addresses: 64
  • Usable Hosts: 62
  • CIDR Prefix: /26
  • Subnet Mask: 255.255.255.192

This means that any device with an IP address from 172.16.50.65 to 172.16.50.126 is on the same network, which is identified by 172.16.50.64 and has a broadcast address of 172.16.50.127.

Using this calculator simplifies the complex binary calculations involved in subnetting, making network design and troubleshooting much more efficient.

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