IPv4 Subnet Calculator
The IP Subnet Calculator helps you quickly calculate subnet details like the broadcast address, subnet, Cisco wildcard mask, and host range by entering your network address, subnet mask, and required hosts.
Table of Contents
About the IPv4 Subnet Calculator
The subnet calculator is based on the classical approach of IP addressing and observes the following principles:
First octet ranging from 1 to 126 a Class A address (binary address in this class starts with 0). First octet ranging from 128 to 191 a Class B address (binary address in this class starts with 10). First octet ranging from 192 to 223 a Class C address (binary address in this class starts with 110). The Online JSON Formatter also allows for the inclusion of only one subnet bit extension. For instance, it is acceptable to use the class C address that has a subnet mask of 255.255.255.128.
Additionally, the calculator makes provision for a situation where the last octet of the subnet id is equal to that of the subnet mask. Consider the following case, a class C network address 192.168.0.192 with a subnet mask 255.255.255.192.
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Frequently Asked Questions About IPv4 Subnet Calculator
A Subnet (Subnetwork) is an independent network which is embedded into a noticeable network. It enables a network administrator to split a single large network into smaller sections which can be easier to work on. There is a reason why such a technique called subnetting exists and that is because it helps reduce strain on the network and improve security as well as management of the network.
For instance there is a network built including many devices utilising different subnets. Each subnet or even every block of devices in the devices can manage a smaller number of devices connected to the network. This way it is possible to control the general network and manage efficiency better.
Subnetting is a process which allows network resources to be used more efficiently by splitting ip address into two pieces: For example, take an IP address like 180.70.90.20 ipv4 addresses are assigned only for hosts and networks, not for links.
- Network part: this explains which network this address is.
- Host part: this specifies the devices (hosts) within that network.
A subnet mask is a 32-bit figure that is utilized to separate a network address from the host address in a given IP, that is, the network identification and the devices using the network.
All subnet masks are also expressed in dotted decimal notation as IP addresses like 255.255.255.0. Elsewhere, subnet masks are histograms with the first row filled with 1's while the subsequent rows have slabs of 0's at the bottom. The 1's correspond to the address of the network concerned while the 0's are for addressing devices connected within that network.
For illustration
- 255.255.255.0 The first 24 bits (1's) of the address are the network and the last 8 bits (0's) are the hosts.
- 255.255.255.128 the first 25 bits are used for the network, and the last 7 bits are for the host.
A subnet mask helps in addressing the maximum size of the subnet, as well as the total number of IP addresses for host devices that can be provisioned in that segment.
CIDR (Classless Inter-Domain Routing) notation is an alternative to traditional subnetting methods that allows for more flexibility in assigning IP addresses. CIDR notation uses a format like IP Address/Prefix Length (e.g., 192.168.1.0/24), where:
- The IP address represents the starting address of the network.
- The prefix length (after the slash) indicates the number of bits used for the network portion.
For example:
- 192.168.1.0/24 means that the first 24 bits are used for the network address (equivalent to a subnet mask of 255.255.255.0).
CIDR notation allows more precise management of IP address assignment, thus facilitating the implementation of subnets of various dimensions. Such an approach removes the strict limitations imposed by the classful addressing scheme and ensures better utilization of the address space available.
Calculating network and IP properties involves several steps:
Determine the network addressPerform a bitwise AND operation between the IP address and subnet mask. This operation helps you identify the network portion of the IP address.
Calculate the broadcast addressThe broadcast address is used to send data to all devices on the network. To calculate it, take the network address and set all host bits to 1.
Determine the range of usable IP addressesThe first usable IP address is the network address + 1, and the last usable IP address is the broadcast address - 1.
Calculate the number of available hostsThe number of available hosts is determined by the number of 0 bits in the subnet mask. The formula is 2^n - 2, where n is the number of host bits. Subtracting 2 accounts for the network and broadcast addresses, which cannot be assigned to hosts.
The IP subnet calculator makes subnetting a lot easier by doing all those calculations for you. This is the way to go about it: Enter an IP address:
Enter the IP address
Input the network IP address you are working with (e.g.,192.168.1.0).
Enter the subnet mask or CIDR prefix
put in the relevant subnet mask (for example, 255.255.255.0) or CIDR prefix (for example,/24).
Calculate
Press the “Calculate” button in order to receive the comprehensive details of the network that contain:
- Network address
- Broadcast address
- Host range
- Number of usable hosts
- Subnet size
Some calculators also provide additional details like wildcard masks, binary equivalents, and more. You can use these tools to quickly determine subnet properties without manually performing bitwise operations.
Let’s do a sample calculation for IP address 192.168.10.0 with subnet mask 255.255.255.192 (or /26):
- IP Address – 192.168.10.0
- The Subnet Mask – 255.255.255.192 (or /26)
- Network Address – 192.168.10.0 (it refers to receiving the result of an IP and the subnet mask version addressed by logical AND operations).
- Broadcast Address – 192.168.10.63 (setting every host bit as 1 in the IP address).
- Usable Host Range: 192.168.10.1 through 192.168.10.62 (since the first and last ones are assumed to be contained in the network number and the broadcast address respectively).
- Number of Usable Hosts: 62 hosts (- 2, calculated as 2^6, where six are the host bits).
