Find Ip Address Range Calculator

Calculate IP Range

Results Table & Chart

Network Address	First Usable	Last Usable	Broadcast Address	Total Hosts	Usable Hosts
—	—	—	—	—	—

Summary of the calculated IP address range details.

What is an IP Address Range Calculator?

An IP Address Range Calculator is a tool used to determine various network parameters based on an IP address and a subnet mask (or CIDR prefix). It calculates the network address, broadcast address, the range of usable IP addresses within that subnet, the total number of hosts, and the number of usable hosts. It's essential for network planning, configuration, and troubleshooting.

Network administrators, IT professionals, students learning about networking, and anyone working with IP networks use an IP Address Range Calculator to understand and manage subnets. It helps in efficiently allocating IP addresses and ensuring proper network communication.

A common misconception is that this calculator finds *your* current IP address. While it deals with IP addresses, its purpose is to analyze a given IP and mask to define a network range, not to discover the IP of the device you are using (for that, you'd look for a "What is my IP" tool).

IP Address Range Calculator Formula and Mathematical Explanation

The core of the IP Address Range Calculator involves bitwise operations on the binary representations of the IP address and the subnet mask.

1. Convert to Binary: Both the IP address and the subnet mask are converted from dotted decimal notation to their 32-bit binary equivalents.
2. Network Address: A bitwise AND operation is performed between the binary IP address and the binary subnet mask. The result, converted back to dotted decimal, is the network address. Network Address = IP Address AND Subnet Mask
3. Broadcast Address: First, the subnet mask is inverted (bitwise NOT), also called the wildcard mask. Then, a bitwise OR operation is performed between the binary IP address and the inverted subnet mask (or more accurately, the network address ORed with the wildcard mask). The result is the broadcast address. Broadcast Address = Network Address OR Wildcard Mask
4. Total Hosts: If the CIDR prefix is 'c', the number of bits for the host portion is 32-c. The total number of addresses (including network and broadcast) is 2^(32-c).
5. Usable Hosts: For most networks (CIDR < 31), the number of usable host addresses is the total number of addresses minus 2 (one for the network address and one for the broadcast address). For /31, it's 2 total, 0 or 2 usable depending on RFC 3021 context, but often considered 0 in simple calcs for host assignment. For /32, it's 1 total, 1 usable (a host route).
6. First Usable IP: Network Address + 1 (incrementing the last octet, carrying over if necessary).
7. Last Usable IP: Broadcast Address – 1 (decrementing the last octet, borrowing if necessary).

Variables Table

Variable	Meaning	Unit/Format	Typical Range
IP Address	The 32-bit IPv4 address	Dotted Decimal	0.0.0.0 to 255.255.255.255
Subnet Mask	A 32-bit mask defining network/host portions	Dotted Decimal	e.g., 255.0.0.0, 255.255.0.0, 255.255.255.0
CIDR	Classless Inter-Domain Routing prefix length	Integer	0 to 32
Network Address	The first address in the range, identifies the network	Dotted Decimal	Varies
Broadcast Address	The last address, used to send data to all hosts	Dotted Decimal	Varies
Total Hosts	Total number of addresses in the block	Integer	1 to 2^32
Usable Hosts	Number of addresses assignable to devices	Integer	0 to 2^32-2

Variables used in IP address range calculations.

Practical Examples (Real-World Use Cases)

Example 1: Small Office Network

Imagine a small office using the IP address 192.168.1.55 with a subnet mask of 255.255.255.0 (or /24). Using the IP Address Range Calculator:

• IP Address: 192.168.1.55
• Subnet Mask: 255.255.255.0 (/24)
• Network Address: 192.168.1.0
• Broadcast Address: 192.168.1.255
• First Usable IP: 192.168.1.1
• Last Usable IP: 192.168.1.254
• Total Hosts: 256
• Usable Hosts: 254

This tells the admin they can assign IPs from 192.168.1.1 to 192.168.1.254 to devices in that office.

Example 2: Larger Department Network

A department is assigned the IP 10.10.34.100 with a /22 CIDR. Using the IP Address Range Calculator:

• IP Address: 10.10.34.100
• CIDR: /22 (Subnet Mask: 255.255.252.0)
• Network Address: 10.10.32.0
• Broadcast Address: 10.10.35.255
• First Usable IP: 10.10.32.1
• Last Usable IP: 10.10.35.254
• Total Hosts: 1024
• Usable Hosts: 1022

The department has a range from 10.10.32.1 to 10.10.35.254 for its devices.

How to Use This IP Address Range Calculator

1. Enter IP Address: Type the IPv4 address you want to analyze into the "IP Address" field (e.g., 172.16.0.10).
2. Select Mask Format: Choose whether you want to input the subnet mask as CIDR (like /24) or Dotted Decimal (like 255.255.255.0).
3. Enter Subnet Mask/CIDR: Based on your selection, either choose the CIDR from the dropdown or type the subnet mask into the text field.
4. Calculate: Click the "Calculate" button (though results update automatically as you type or change selections).
5. Review Results: The calculator will instantly display the Network Address (primary result), Broadcast Address, First and Last Usable IPs, Total and Usable Hosts, the mask in both formats, Wildcard Mask, IP Class, and Type (Private/Public). The table and chart will also update.
6. Interpret: The "First Usable IP" to "Last Usable IP" range is what you can assign to devices. The "Network Address" and "Broadcast Address" are reserved.

Key Factors That Affect IP Address Range Calculator Results

• IP Address Value: The specific IP address entered determines which subnet it falls into, given a mask.
• Subnet Mask/CIDR Value: This is the most critical factor. It defines the size of the network and host portions, directly impacting the number of total and usable hosts, and the network/broadcast addresses. A smaller CIDR (like /16) means more hosts than a larger CIDR (like /24).
• IP Version: This calculator is for IPv4. IPv6 uses a completely different addressing scheme (128 bits) and subnetting logic.
• Private vs. Public IP Ranges: The calculator identifies if the IP falls within IANA-reserved private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16). This affects where the IP can be routed (private IPs are not internet-routable without NAT).
• CIDR /31 and /32: These are special cases. /32 defines a single host, and /31 is often used for point-to-point links with 2 total addresses, sometimes considered 0 usable for general hosts, but 2 for the link itself per RFC 3021.
• Subnetting Plan: In a larger network, the choice of subnet mask is part of a broader subnetting plan to divide a large address block into smaller, manageable subnets. The IP Address Range Calculator helps visualize one such subnet.

Frequently Asked Questions (FAQ)

What is CIDR?

CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and routing IP packets. The CIDR notation (e.g., /24) represents the number of leading '1' bits in the subnet mask, indicating the network portion of the address.

What is a Subnet Mask?

A subnet mask is a 32-bit number that divides an IP address into network and host portions. The '1's in the mask correspond to the network portion, and the '0's correspond to the host portion. Our IP Address Range Calculator can work with both CIDR and dotted-decimal subnet masks.

Why are there 2 fewer usable hosts than total hosts?

In a typical subnet (CIDR < 31), two addresses are reserved: the first address is the Network Address (identifying the network), 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.

What is the maximum number of usable hosts in an IPv4 network?

The largest block typically allocated is a /8, giving 2^(32-8) = 2²⁴ = 16,777,216 total addresses, or 16,777,214 usable hosts.

Can I use /31 or /32 CIDR?

Yes. A /32 represents a single host address (1 total, 1 usable). A /31 represents a network with 2 total addresses, often used for point-to-point links (see RFC 3021), where both addresses can be considered usable for the link endpoints, though our calculator shows 0 or 2 depending on interpretation for general host assignment.

What are private IP address ranges?

Private IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) are reserved for use within private networks and are not routable on the public internet. The IP Address Range Calculator identifies these.

What is a Wildcard Mask?

A wildcard mask is the bitwise inverse of the subnet mask. It's often used in access control lists (ACLs) on routers and firewalls to specify a range of IP addresses.

How does the IP Address Range Calculator handle invalid input?

The calculator validates the IP address and subnet mask formats. If you enter an invalid IP (e.g., 300.1.1.1) or an invalid mask, it will show an error message and won't perform the calculation until valid input is provided.

Related Tools and Internal Resources

• Subnet Calculator: Explore different subnetting scenarios based on network size or host requirements.
• CIDR Calculator: Quickly convert between CIDR, subnet mask, and wildcard mask.
• What is My IP: Find your public IP address.
• IPv4 vs IPv6: Understand the differences between the two IP versions.
• Private IP Addresses Explained: Learn more about private IP address ranges and their use.
• Network Addressing Basics: A fundamental guide to IP addressing and subnetting.