Find Ip Range Calculator

Easily calculate the network address, broadcast address, usable host range, and more from an IP address and subnet mask or CIDR prefix with our IP Range Calculator.

IP Range Calculator

Address Details

Item	Decimal	Binary
IP Address
Subnet Mask
Network Address
Broadcast Address

What is an IP Range Calculator?

An IP Range Calculator is a tool used by network administrators, IT professionals, and students to determine the various addresses and properties associated with a given IPv4 address and its subnet mask or CIDR prefix. Based on these inputs, the calculator can find the Network Address, Broadcast Address, the range of usable IP addresses for hosts within that subnet, the total number of hosts, and the number of usable hosts. The IP Range Calculator is essential for planning and managing IP address allocation within a network.

Anyone working with network configurations, subnetting, or studying for networking certifications (like CCNA) will find an IP Range Calculator extremely useful. It helps visualize how a block of IP addresses is divided and what parts are reserved for network and broadcast purposes.

Common misconceptions include thinking the calculator finds *your* computer’s IP range automatically (it requires you to input an IP and mask) or that it can find ranges for any IP address without a mask (the mask/CIDR is crucial for defining the range).

IP Range Calculator Formula and Mathematical Explanation

The calculations performed by an IP Range Calculator are based on bitwise operations on the binary representations of the IP address and the subnet mask.

1. Convert to Binary: The IP address and subnet mask are converted from their dotted-decimal format to 32-bit binary numbers.
2. Network Address: The Network Address is found by performing a bitwise AND operation between the IP address and the subnet mask.
   
   Network Address = IP Address AND Subnet Mask
3. Broadcast Address: The Broadcast Address is typically found by taking the Network Address and setting all host bits (the bits that are 0 in the subnet mask) to 1. Alternatively, it’s the Network Address OR the inverted (NOT) Subnet Mask (also known as the wildcard mask), but only considering the 32-bit boundary. A more reliable way is Network Address + (Total Hosts – 1).
4. Total Hosts: If the CIDR prefix is ‘c’, there are 32-c bits for the host portion. The total number of addresses in the subnet is 2^(32-c).
5. Usable Hosts: The first address (Network Address) and the last address (Broadcast Address) are reserved and cannot be assigned to hosts. So, Usable Hosts = 2^(32-c) – 2. For /31 and /32, this is different (0 or 1 usable, respectively, for point-to-point or loopback).
6. First Usable Host: Network Address + 1.
7. Last Usable Host: Broadcast Address – 1.
8. Wildcard Mask: The inverse of the subnet mask (0s become 1s, 1s become 0s).

Variables Table

Variable	Meaning	Unit/Format	Typical Range
IP Address	The input IPv4 address	Dotted Decimal	0.0.0.0 to 255.255.255.255
Subnet Mask	The mask defining network/host portions	Dotted Decimal	e.g., 255.0.0.0 to 255.255.255.255
CIDR Prefix	Number of network bits	Integer	0 to 32
Network Address	First address in the range	Dotted Decimal	Depends on IP & Mask
Broadcast Address	Last address in the range	Dotted Decimal	Depends on IP & Mask
Total Hosts	Total addresses in the subnet	Integer	1 to 2^32
Usable Hosts	Addresses available for devices	Integer	0 to 2^32-2

Our subnet calculator can help you explore these variables further.

Practical Examples (Real-World Use Cases)

Let’s see the IP Range Calculator in action.

Example 1: Home Network

• Input IP Address: 192.168.1.150
• Input CIDR: /24 (or Subnet Mask: 255.255.255.0)
• Network Address: 192.168.1.0
• Broadcast Address: 192.168.1.255
• First Usable: 192.168.1.1
• Last Usable: 192.168.1.254
• Total Hosts: 256
• Usable Hosts: 254

Interpretation: For a device with IP 192.168.1.150 and mask 255.255.255.0, it belongs to the 192.168.1.0 network, and you can assign IPs from 192.168.1.1 to 192.168.1.254 to devices on this network.

Example 2: Small Business Department Subnet

• Input IP Address: 10.10.20.70
• Input CIDR: /27 (or Subnet Mask: 255.255.255.224)
• Network Address: 10.10.20.64
• Broadcast Address: 10.10.20.95
• First Usable: 10.10.20.65
• Last Usable: 10.10.20.94
• Total Hosts: 32
• Usable Hosts: 30

Interpretation: An IP 10.10.20.70 with a /27 prefix is in the 10.10.20.64 network, which can accommodate up to 30 devices (from 10.10.20.65 to 10.10.20.94). This is useful for segmenting a larger network. Learn more about what is CIDR and subnetting.

How to Use This IP Range Calculator

1. Enter IP Address: Input the IPv4 address you want to analyze (e.g., 172.16.30.5).
2. Select Mask Format: Choose whether you want to enter the subnet mask as a CIDR prefix (like /24) or in dotted decimal format (like 255.255.255.0).
3. Enter CIDR or Subnet Mask: Based on your selection, enter the CIDR value (0-32) or the full subnet mask. The other field will update automatically.
4. Click Calculate (or observe real-time updates): The calculator will automatically update the results as you type or change inputs.
5. Read the Results:
   • Primary Result: Shows the Network/CIDR and the range of usable IPs.
   • Intermediate Results: Details like Network Address, Broadcast Address, Total and Usable Hosts, Wildcard Mask, and IP Class are displayed.
   • Table and Chart: The table provides decimal and binary representations, while the chart visualizes IP allocation.
6. Copy Results: Use the “Copy Results” button to copy the key information to your clipboard.

This IP Range Calculator helps you quickly understand the boundaries and size of a network segment based on an IP and its mask.

Key Factors That Affect IP Range Results

The results from an IP Range Calculator are directly determined by two main factors:

1. IP Address: While the IP address itself doesn’t define the range size, it determines *which* specific range is being calculated within a larger address space, once the mask is applied.
2. Subnet Mask or CIDR Prefix: This is the most crucial factor. The subnet mask (or its CIDR equivalent) defines how many bits are used for the network portion and how many are left for the host portion. A larger CIDR (more network bits, e.g., /27) means fewer host bits, resulting in a smaller range with fewer usable IPs. A smaller CIDR (e.g., /16) means more host bits and a larger range.
3. Network vs. Host Bits: The balance between network and host bits (defined by the mask/CIDR) dictates the number of subnets you can create and the number of hosts per subnet.
4. Reserved Addresses: Every subnet (except /31 and /32 in specific cases) loses two addresses: one for the network address and one for the broadcast address. This reduces the number of usable IPs.
5. IP Version (IPv4 vs IPv6): This calculator is for IPv4. IPv6 uses a 128-bit address and different subnetting principles, though the idea of network and host portions remains.
6. Private vs. Public IP Ranges: The calculation is the same, but private IP ranges (like 192.168.x.x, 10.x.x.x, 172.16.x.x-172.31.x.x) are not routable on the public internet and are intended for internal networks. Our IP lookup tool can give more info on a public IP.

Frequently Asked Questions (FAQ)

Q1: What is a subnet mask?

A subnet mask is a 32-bit number that masks an IP address and divides the IP address into network address and host address. It’s used to identify which part of an IP address is the network portion and which is the host portion.

Q2: What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation is a compact way to represent a subnet mask. It’s shown as a slash (/) followed by a number (e.g., /24), where the number indicates how many bits are used for the network portion of the address.

Q3: Why are two IP addresses unusable in most subnets?

The first address in a subnet is the Network Address (identifies the network itself), and the last address is the Broadcast Address (used to send data to all hosts on the subnet). These cannot be assigned to individual devices, making them “unusable” for hosts.

Q4: Can I use a /31 or /32 CIDR?

Yes. A /31 is often used for point-to-point links, allowing for 2 total addresses (0 usable in the traditional sense, but both used for the link endpoints). A /32 represents a single host address (1 total, 1 usable – the host itself), often used for loopback interfaces or specific host routes.

Q5: How does the IP Range Calculator work?

It takes the IP address and subnet mask (or CIDR), converts them to binary, performs bitwise operations (AND for network address, etc.), and calculates the host range and counts based on the number of host bits.

Q6: What’s the difference between total hosts and usable hosts?

Total hosts is the total number of IP addresses within the calculated range (2^(32-CIDR)). Usable hosts is the number of addresses that can be assigned to devices, which is total hosts minus 2 (for network and broadcast addresses), except for /31 and /32.

Q7: How do I choose the right subnet mask or CIDR for my network?

You need to determine the number of hosts you need to support in each subnet and the number of subnets you require. This will guide you in selecting a subnet mask/CIDR that provides enough host addresses per subnet while allowing for the desired number of subnets. More on IP addressing basics here.

Q8: Is this IP Range Calculator for IPv4 or IPv6?

This calculator is specifically designed for IPv4 addresses. IPv6 addressing and subnetting are different due to the 128-bit address length.

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