Free Subnet Calculator

IP subnet calculator is an easy-to-use online tool designed to help network administrators and IT professionals quickly and accurately calculate subnets on a network and use this information for network subnetting

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Subnet Calculator

Address Block

IP Address (IPv4)

Mask bits

Network Mask255.255.255.0

Subnet Allocation

Subnet bits

Number of subnets

Addresses per subnet126

IP Address	192								168								1								1
Octet Value	C0								A8								1								1
Octet Number	1								2								3								4
Bit Number	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32
Bit Value	1	1	0	0	0	0	0	0	1	0	1	0	1	0	0	0	0	0	0	0	0	0	0	1	0	0	0	0	0	0	0	1

All Subnets
Subnet	Start Address	End Address	Network Address	Broadcast Address

What is a subnet calculator and how can I use it?

How does our free subnet calculator tool work?

Start simply with inserting an IPv4 IP address in the online subnet calculator and specify its network mask (Mask bits) in CIDR notation. Then, based on your requirements, specify subnet size by choosing subnet mask (number of subnet bits) and number of subnets you’re looking for. Based on these parameters, subnet calculator will immediately display the number of available IP addresses per subnet, and a range of IP addresses for each of the subnets, including start address, end address, network address, and broadcast address.

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What can you use the free IP subnet calculator to do?

The subnet calculator can help you with network subnetting. Although you can calculate subnets for your network manually, this process is extremely time-demanding and prone to errors such as the overlapping of two subnets—this could potentially result in routing problems as one address exists in more subnets. Use our free network subnet calculator to make your work more efficient and design your network as needed.

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Get more features with IP Address Manager

Integrated DHCP, DNS, and IP address management

If you’re looking to take your subnet calculator features and general IP address management capabilities further, you need a tool like SolarWinds^® IP Address Manager (IPAM). IPAM offers:

Automated IP address tracking
IP address alerting, troubleshooting, and reporting
Simplified subnet, supernet, and group creation

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Get More on IP Subnet Calculator

Do you find yourself asking…

What is subnetting?
What is a subnet mask?
Why should I subnet a network?
How to calculate a subnet?
What is the difference between IPv4 and IPv6 subnetting?
What is a supernet calculator?
What are the difficulties connected to subnetting?

Subnetting is the process of breaking down a single network into one or more smaller networks called “sub-networks” or “subnets” for short. The process of subnetting was initially created to solve the shortage of IP addresses over the internet but has since evolved into an IP management best practice for IP network utilization.

Every IP address is comprised of three different classes or major networks – Class A, Class B, and Class C. Without subnets, you’d only be able to use one network from each class, which isn’t the most efficient way to work.

Subnetting allows network administrators to take bits from the IP address’s host part and use these bits to create smaller networks inside the network. These smaller networks are built up of many other IP addresses sharing the same IP routing prefix as the original IP address used to create the subnets. Once you have these smaller networks, you create a network of interconnecting subnetworks to distribute your network’s load more efficiently.

It’s critically important for network administrators in large enterprises to subnet because reorganizing the network in such a way makes it more functional. For a single IP subnet to handle everything happening in a large enterprise, it would have to be incredibly large—which means it would be inherently unwieldy.

You might end up with:

Unnecessary network traffic from hosts handling broadcasts sent over a single subnet

Network security concerns caused by secured and unsecured servers using the same subnet

A poorly organized overall structure

You should use a network subnet calculator to subnet your network for three primary reasons.

Organizational Efficiency: When it comes to partitioning a large enterprise’s network and dividing resources accordingly, subnetting the network gives you several different options. For example, if you divide your network into subnets based on departments, you’ll be able to easily identify which department is having problems by looking at the IP address alone. This facilitates faster troubleshooting and makes it easier for you to find info related to a specific department. Subnetting with the help of a network subnet calculator allows you to compartmentalize and organize your network in a logical manner.

Network Security: One of the biggest disadvantages of working within an unsubnetted network is it can compromise network security. When devices use the same subnet, these devices can freely communicate with one another and share information. This can pose a problem if a server containing sensitive information and an employee workstation share the same subnet. At best, an employee might accidentally gain access to confidential information. At worst, a cyberattacker could gain access to confidential information and critical systems housed on the subnet by leveraging access to an employee workstation. Subnetting allows you to set and maintain clear barriers within the network to control departmental access.

Operational Efficiency: Network administrators first started subnetting because creating and setting aside millions of unused IPv4 was a waste of time and effort. Extending the range of your IP addresses by creating subnets helps you scale and makes your network more functional. If you have too many subnet masks, changing the size of the subnet by adjusting the subnet mask will free up more IP addresses for other subnets. Subnetting makes better use of your organization’s existing IP addresses and network resources.

These three benefits are only the beginning when it comes to subnetting—a network subnet calculator can help you unlock even more.

Subnetting is the process of breaking down a single network into one or more smaller networks called “sub-networks” or “subnets” for short. The process of subnetting was initially created to solve the shortage of IP addresses over the internet but has since evolved into an IP management best practice for IP network utilization.

Every IP address is comprised of three different classes or major networks – Class A, Class B, and Class C. Without subnets, you’d only be able to use one network from each class, which isn’t the most efficient way to work.

Subnetting allows network administrators to take bits from the IP address’s host part and use these bits to create smaller networks inside the network. These smaller networks are built up of many other IP addresses sharing the same IP routing prefix as the original IP address used to create the subnets. Once you have these smaller networks, you create a network of interconnecting subnetworks to distribute your network’s load more efficiently.

It’s critically important for network administrators in large enterprises to subnet because reorganizing the network in such a way makes it more functional. For a single IP subnet to handle everything happening in a large enterprise, it would have to be incredibly large—which means it would be inherently unwieldy.

You might end up with:

Unnecessary network traffic from hosts handling broadcasts sent over a single subnet

Network security concerns caused by secured and unsecured servers using the same subnet
A poorly organized overall structure
You should use a network subnet calculator to subnet your network for three primary reasons.
Organizational Efficiency: When it comes to partitioning a large enterprise’s network and dividing resources accordingly, subnetting the network gives you several different options. For example, if you divide your network into subnets based on departments, you’ll be able to easily identify which department is having problems by looking at the IP address alone. This facilitates faster troubleshooting and makes it easier for you to find info related to a specific department. Subnetting with the help of a network subnet calculator allows you to compartmentalize and organize your network in a logical manner.

Network Security: One of the biggest disadvantages of working within an unsubnetted network is it can compromise network security. When devices use the same subnet, these devices can freely communicate with one another and share information. This can pose a problem if a server containing sensitive information and an employee workstation share the same subnet. At best, an employee might accidentally gain access to confidential information. At worst, a cyberattacker could gain access to confidential information and critical systems housed on the subnet by leveraging access to an employee workstation. Subnetting allows you to set and maintain clear barriers within the network to control departmental access.

Operational Efficiency: Network administrators first started subnetting because creating and setting aside millions of unused IPv4 was a waste of time and effort. Extending the range of your IP addresses by creating subnets helps you scale and makes your network more functional. If you have too many subnet masks, changing the size of the subnet by adjusting the subnet mask will free up more IP addresses for other subnets. Subnetting makes better use of your organization’s existing IP addresses and network resources.

These three benefits are only the beginning when it comes to subnetting—a network subnet calculator can help you unlock even more.
The process of subnetting simply means creating a subnetwork (or subnet) within a network. All of the network devices and interfaces within a subnet can communicate directly while routers facilitate communication between multiple subnets. An IP range calculator can deliver insights into individual subnets to simplify management.

Subnetting offers a number of benefits including better network performance and stronger network security. However, it also has some limitations. These include:

Needing a router to communicate between subnets—if a router is poorly configured or failed, your organization’s network can suffer

IP addresses can be wasted given that every subnet needs dedicated IP addresses as subnet IDs and broadcast addresses
The potential for unnecessary complexity that interferes with the effectiveness of your network administration if you create too many subnets
Luckily, all of these difficulties can be addressed with the right tool. In addition to offering a powerful free subnetting calculator, SolarWinds also offers SolarWinds^®IP Address Manager (IPAM), management software that’s designed to make administrators’ lives easier while helping your network run more smoothly. IPAM not only makes subnetting (and managing subnets) simpler, helping you prevent the potential limitations of the process, but it also includes IP scanning, monitoring, and alerting features that ensure you’re aware any time an error arises within your subnets.

You can try IPAM free for 30 days.

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