On this FAQ page, you'll find detailed answers to the questions about the subnet calculator, subnetting, and IP addressing.
The subnet calculator is an online tool to determine various network parameters based on the provided IP address and subnet mask or CIDR notation. It helps network administrators, IT professionals, and students divide an IP network into multiple smaller, manageable sub-networks, called subnets.
A subnet (short for subnetwork) is a segmented piece of a larger network. Subnets divide a large IP network into smaller and more manageable sections. This is done to enhance network performance, improve security, and organize infrastructure more efficiently.
For example, instead of one flat network with 500 devices, subnetting can divide it into smaller groups, like 5 subnets of 100 devices each. This reduces traffic congestion and helps isolate faults or security threats.
Subnetting is the process of dividing a network into smaller subnetworks or subnets. It involves manipulating the IP address and subnet mask to determine the network and host portions of the address.
Subnetting allows:
Calculating subnets manually requires understanding binary arithmetic and IP address structure. A subnet calculator makes this process fast, accurate, and stress-free.
With our calculator, you can:
CIDR stands for Classless Inter-Domain Routing. It replaces the older class-based IP addressing system and offers more flexibility. In CIDR notation, the IP address is written with a slash and a number after it. For example: 192.168.1.0/24. The number '24' indicates the number of bits used for the network portion.
A subnet mask determines which part of the IP address is the network and which is the host. It is written in the same format as an IP (Example: 255.255.255.0).
Each octet of the mask corresponds to the same part of the IP address, helping devices determine if another IP is within the same subnet.
Example:
The network address is the first address in a subnet. It represents the subnet itself and cannot be assigned to a host. For example, in the subnet 192.168.1.0/24, the network address is 192.168.1.0
The broadcast address is the last address in a subnet. It's used to send data to all devices in that subnet simultaneously. Broadcast addresses are important in tasks like device discovery and announcements.
Example:
A host IP address is an assignable IP within the subnet that identifies a specific device. All addresses between the network and broadcast addresses are usable for hosts.
For 192.168.1.0/24, the usable host range is between 192.168.1.1 and 192.168.1.254.
The number of usable host addresses is calculated as:
The subtraction accounts for:
Example:
A wildcard mask is the inverse of the subnet mask and is commonly used in ACLs (Access Control Lists). It defines which parts of an IP address can vary. Wildcard masks are mainly used in routing protocols and firewall configurations.
For example:
Private IP ranges include:
Our subnet calculator works for both public and private IP addresses.
Before CIDR, IP addresses were grouped into classes:
| Class | Start IP | End IP | Default Subnet |
|---|---|---|---|
| A | 1.0.0.0 | 126.255.255.255 | /8 |
| B | 128.0.0.0 | 191.255.255.255 | /16 |
| C | 192.0.0.0 | 223.255.255.255 | /24 |
These classes are mostly obsolete today, replaced by CIDR.
Yes, the tool supports both IPv4 and IPv6 subnetting.
It contains just one IP address and is used to refer to a single host. It's often used in routing tables or when assigning an IP to a loopback interface. There are no usable hosts in a /32 subnet because it refers to a single device.
The calculator prevents overlaps and shows clear subnet ranges. However, when planning a network with multiple subnets, it's your responsibility to ensure that no subnets overlap unless you're using VLSM or route summarization techniques.
Subnetting helps define routed networks, while bridging is more suitable for smaller or simpler networks.
Understanding binary can be helpful, especially when learning how IP addresses and subnet masks work at a low level. However, with our subnet calculator, you don't need to perform binary math manually. It does the heavy lifting for you.
Absolutely! Our tool is widely used by students, instructors, and professionals. It's ideal for:
Our calculator is optimized for:
No. We respect your privacy. Your input data (IP addresses or subnet masks) is processed in real-time on your browser and is not stored or tracked. We do not collect or share any personal or networking data.
Follow the steps below:
(2^host bits) - 2.Yes, our tool is completely free to use. You don't need to create an account, download anything, or sign up. Simply enter your IP address and subnet, and you're all set!