This IP subnet calculator displays comprehensive information about IPv4 networks (e.g., the number of usable hosts, IP ranges, etc.) and IP addresses (e.g., private or public, class, etc.). It's useful for designing networks, troubleshooting, and helping you pass your CompTIA Network+ exam. Show
In the following article, you can read more about CIDR notation and find out what a subnet mask is. Are you interested in administrating networks? You might find our chmod calculator useful, as it helps you understand and solve file permissions issues! What is a subnet?In an Internet Protocol (IP) network, part of the IP address represents the network, while the remainder represents the host (or computer on the network). The act of dividing the IP address is called subnetting. Routers use the network part to exchange data between subnets, and the host part to send data to an individual host. You can estimate how long it will take using the bandwidth calculator. Note, that this IP subnet calculator is applicable to IPv4 networks, though it also shows the IPv4-mapped IPv6 address, and the 6to4 prefix address, used for transitioning to IPv6. What is a subnet mask?When designing a network, it's good practice to balance the network and host parts of the IP address, so as not to have too many (limits the number of networks you can route to) or too few hosts (limits the number of computers on the network). A subnet mask is used to create a subnet by allocating several bits in the 32-bit IP address to represent the network. The remaining bits of the IP address represent the host address. The following table shows an example of an IP address ( Binary form IP address
Subnet mask
Network prefix
Host part
You may find the binary calculator useful if you're unfamiliar with binary operations or need a refresher. CIDR notationIn the early days of the Internet, there were three different main subnet masks, using multiples of 8 bits of ones in the mask. They were named Class A, Class B, and Class C networks, as we show in this table: Subnet mask Number of usable hosts Class A
16,777,214 Class B
65,534 Class C
254 The problem with this scheme is that the choice of the number of hosts per network is rather coarse, with large jumps in the number of hosts per network. The solution is Classless Inter-Domain Routing (CIDR), which eliminates the class model, and lets the network designer assign any number of bits to the network prefix, opening up a more extensive choice of the number of hosts per network. The notation to indicate the number of bits in the network prefix is a forward-slash, followed by the number of bits. So, a Class A network would be written as CIDR Subnet mask Number of usable hosts /1
2,147,483,646 /2
1,073,741,822 /3
536,870,910 /4
268,435,454 /5
134,217,726 /6
67,108,862 /7
33,554,430 /8
16,777,214 /9
8,388,606 /10
4,194,302 /11
2,097,150 /12
1,048,574 /13
524,286 /14
262,142 /15
131,070 /16
65,534 /17
32,766 /18
16,382 /19
8,190 /20
4,094 /21
2,046 /22
1,022 /23
510 /24
254 /25
126 /26
62 /27
30 /28
14 /29
6 /30
2 /31
0 /32
0 Rather than looking up network properties in a table, use this IP address subnet calculator as a CIDR calculator to display the associated network properties. How to calculate network and IP properties?This IP subnet calculator shows you a multitude of network and IP address properties. Let's go through each one to briefly explain how to manually calculate them, linking to further resources for further information. IP type – public or private?There are two main types of IP address, public and private. Servers on the public Internet use public addresses, while local networks of computers (e.g., your home network) use private addresses. The following IP address ranges are private addresses:
IP classAs well as the network class, IP addresses also historically belonged to classes. The range of IP addresses belonging to each class is defined as:
Class D addresses are reserved for multicast traffic (one host sending the same data to many receiving hosts). Class E is reserved, meaning those addresses will not work on the public Internet. Network addressThe network IP address is the first address of the subnet. You calculate it by converting the IP address and subnet mask to binary and performing a bitwise 🙋 If you're curious how switching between number systems works, visit our binary converter! Broadcast addressA host can use the broadcast address to send data to all the other hosts on the subnet. It's the last address on the subnet. We can calculate it by using the network address and adding the total number of addresses (minus one) in the subnet. First and last host addressesThe next address after the network address is the first address available to be assigned to a host. The address just before the broadcast address is the last address that you can allocate to a host. Wildcard maskThe wildcard mask is the subnet mask with the bits inverted, therefore selecting the host part of the IP address. Total number of addressesWe can calculate the total number of addresses in a subnet from the CIDR using the following formula: total numberof addresses=2(32−CIDR)\qquad \small {\text{total number} \atop \text{of addresses}} = 2^{(32 - \text{CIDR})}of addressestotal number=2(32−CIDR) Usable number of hostsThe network and broadcast addresses are not available to be assigned to hosts on the network. So, the number of available addresses that you can assign to hosts is the total number of addresses minus two. Binary subnet mask and IP addressThese outputs are the subnet mask and IP address converted to binary format. These are helpful when manually subnetting networks. CIDR notationThis result is the IP address in quad-dotted notation, followed by a forward-slash and the CIDR number. IP address in integer and hexadecimal formAn IP address is just a number, so you can represent it as an integer (base 10), hexadecimal (base 16), or any other base you like. in-addr.arpaThis property is a special domain name, used for reverse DNS (Domain Name System) lookups (going from an IP address to a domain name). The IP address (in quad-dotted format) is reversed and prepended to the domain IPv4-mapped IPv6 addressThe Internet is currently upgrading IP addresses from version 4 (represented by 32 bits) to version 6 (represented by 128 bits). To help with this transition, hybrid dual-stack IPv6/IPv4 implementations use a 96-bit prefix of 80 bits of zeros and 16 bits of ones, followed by the 32 bit IP address. For example, the IPv4 address 6to4 prefixAnother IPv4 to IPv6 transition strategy is called 6to4 and allows IPv6 data to travel over IPv4 networks. A 6to4 IPv6 address always starts with How to use the IP subnet calculator?This subnet calculator is straightforward to use. First select the subnet mask you are interested in exploring. You can reduce the list of subnet masks to choose from by setting the network class option. Next, enter the IP address, one octet at a time, in the four rows. You will then see all of the network and IP address properties. Example of calculating network and IP propertiesTaking an example IP address of IP typeCheck if the IP address is within any of the ranges of private IP addresses. If it is, then it is a private address. Otherwise, it is a public address. Looking at the ranges, we see that IP classLooking through the ranges of each class in the previous section, we see that the IP address Network addressLet's go through the calculation of the network address, step-by-step.
So, Total number of addressesNext, we'll calculate the total number of addresses, as we need that to work out the broadcast address. Use the equation for the total number of addresses, given that the CIDR is 24.
So, the total number of addresses is 256. Broadcast addressNow, we can calculate the broadcast address. Convert the network address from binary to decimal, which gives
So, the broadcast address for our example is First and last host addressesFor the first usable host address, we add one to the network address. While you can do all of the converting to a decimal number, adding one, and switching back to the quad-dotted decimal format, usually, it's easy to work directly with the quad-dotted decimal. Adding one to the network address The same can be said when calculating the last usable host address, which is the broadcast address minus one. That gives a result of Wildcard maskTo calculate the wildcard mask, convert the subnet mask to binary and flip all the bits. Then switch back to the quad-dotted decimal format.
The wildcard mask for our example is IP address in integer and hexadecimalUsing the binary form of the IP address, we can convert the binary number to integer (base 10) and hexadecimal (base 16).
in-addr.arpaReverse the example IP address IPv4-mapped IPv6 addressIPv4-mapped IPv6 addresses consist of the prefix
6to4 prefixThe 6to4 prefix consists of
That's a lot of work here, isn't it? Thanks to our IP address subnet calculator, you can obtain all of this information in a minute! FAQHow do I calculate IP range from subnet mask?To calculate the starting address of the subnet:
Then to calculate the last address in the subnet range:
How do I calculate the broadcast address of a subnet?The broadcast address is the last IP address within a subnet. You can calculate it by taking the network address (the 1st address within the subnet), adding the number of addresses in the subnet, and then subtracting one. How many IP addresses are possible with a /26 mask?Explanation: A /26 mask is the same as 255.255.255.192. The mask leaves 6 host bits. With 6 host bits, 64 IP addresses are possible. One address represents the subnet number and one address represents the broadcast address, which means that 62 addresses can then be used to assign to network devices.
What is the usable number of host IP addresses on a network?What is the usable number of host IP addresses on a network that has a /26 mask? Explanation: A /26 mask is the same as 255.255.255.192. The mask leaves 6 host bits. With 6 host bits, 64 IP addresses are possible.
How many IP addresses can be assigned to one subnet?The mask leaves 6 host bits. With 6 host bits, 64 IP addresses are possible. One address represents the subnet number and one address represents the broadcast address, which means that 62 addresses can then be used to assign to network devices.
What is the purpose of the IP address and subnet mask?The combination of the IP addresses and subnet mask allows the device at 192.168.1.101 to figure out if the other device is on the same network (like the device at 192.168.1.103), or on a completely different network somewhere else online.
How many IP addresses are in a 26?A “/26” network provides 64 IPv4 addresses.
What is the usable number of host IP addresses on a network that?In simple words, the Number of hosts in any network can be calculated with the formula = 2x– 2, where x is the number of host ID bits in the IP address.
How many subnets are in a 26?A /26 network has 64 addresses. Since the definition of a subnet is that it contains at least 2 addresses, the technically correct answer is 32.
How many IP addresses are available in a 27 network?Explanation: The network id bits of the given address are 27 bits, which means the host address bits are 5. There are 32 (25) IP addresses possible in this network.
|
