Subnet Calculator
Calculate IPv4 subnet details including network address, broadcast address, usable host range, and subnet mask. Essential tool for network administrators.
IP Address & Subnet
Network
192.168.1.0/24
Class
C
Network Details
| Subnet Mask | 255.255.255.0 | |
| Wildcard Mask | 0.0.0.255 | |
| Network Address | 192.168.1.0 | |
| Broadcast Address | 192.168.1.255 | |
| First Usable | 192.168.1.1 | |
| Last Usable | 192.168.1.254 | |
| Total Hosts | 256 | |
| Usable Hosts | 254 |
Binary Subnet Mask
11111111.11111111.11111111.000000001s represent the network portion, 0s represent the host portion
Private IP Ranges
| Class | Range |
|---|---|
| Class A Private | 10.0.0.0/8 |
| Class B Private | 172.16.0.0/12 |
| Class C Private | 192.168.0.0/16 |
| Localhost | 127.0.0.0/8 |
Our subnet calculator helps network professionals calculate IP subnet details quickly. Enter an IP address and subnet mask (CIDR or dotted decimal) to get network address, broadcast address, first and last usable host addresses, and total host count. Essential for network planning, troubleshooting, and certification exam preparation.
When to Use This Tool
- Planning IP address allocation for a corporate network
- Setting up firewall rules by understanding IP ranges
- Configuring network devices with correct subnet masks
- Dividing a network into smaller subnets for security
- Troubleshooting connectivity issues by understanding subnetting
- Preparing for network certification exams (CCNA, CompTIA)
How to Use
Calculate Subnet Details
- Enter an IP address (e.g., 192.168.1.0)
- Enter subnet mask in CIDR notation (e.g., /24) or dotted decimal (255.255.255.0)
- Click 'Calculate' to see network details
- View usable host range and broadcast address
Understanding the Results
- Network Address: First address in the range (identifies the subnet)
- Broadcast Address: Last address (sends to all hosts in subnet)
- First Host: First usable IP (network address + 1)
- Last Host: Last usable IP (broadcast address - 1)
- Total Hosts: Number of usable IPs in this subnet
Common Subnet Masks
- /24 (255.255.255.0): 254 hosts per subnet
- /25 (255.255.255.128): 126 hosts per subnet
- /26 (255.255.255.192): 62 hosts per subnet
- /27 (255.255.255.224): 30 hosts per subnet
- /28 (255.255.255.240): 14 hosts per subnet
- /30 (255.255.255.252): 2 hosts per subnet (point-to-point links)
Examples
Typical Office Network
Standard subnet for 254 devices like an office floor
Input
IP: 10.0.0.0 | Subnet: /24 (255.255.255.0)
Result
Network: 10.0.0.0 | Range: 10.0.0.1 - 10.0.0.254 | Broadcast: 10.0.0.255 | 254 hosts
Small Department
A smaller 30-host subnet for a department or team
Input
IP: 192.168.1.64 | Subnet: /27 (255.255.255.224)
Result
Network: 192.168.1.64 | Range: 192.168.1.65 - 192.168.1.94 | Broadcast: 192.168.1.95 | 30 hosts
Point-to-Point Link
Used for router-to-router connections, only 2 usable IPs
Input
IP: 10.0.0.0 | Subnet: /30 (255.255.255.252)
Result
Network: 10.0.0.0 | Range: 10.0.0.1 - 10.0.0.2 | Broadcast: 10.0.0.3 | 2 hosts
Frequently Asked Questions
What's the difference between subnet mask and CIDR notation?
Both represent the same thing. Subnet mask uses dotted decimal (255.255.255.0) while CIDR uses slash notation (/24). /24 means '24 bits are network bits' which equals 255.255.255.0. CIDR is shorter and commonly used in routing configurations.
Why do we subtract 2 from total IPs?
In every subnet, the first IP (network address) identifies the network itself and cannot be assigned to hosts. The last IP (broadcast address) is reserved for broadcasting to all hosts. Only IPs between these are available for devices.
What's the difference between public and private IP ranges?
Private IP ranges (RFC 1918) are: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. These aren't routable on the internet - they're for internal networks. Public IPs are unique globally and required for internet connectivity.
Can I use any IP address for my network?
You should use private IP ranges for internal networks to avoid conflicts with public internet. If you're setting up a real network that connects to the internet, you'll need public IPs from your ISP or register your own.
What is VLSM (Variable Length Subnet Masking)?
VLSM allows different subnets to have different sizes, optimizing IP address usage. Instead of all subnets being the same size (like /24), you can have a /26 for 30 hosts, a /30 for 2 hosts, etc. This reduces waste from larger subnets.
Pro Tips
- •When planning subnets, always round up host requirements to the next power of 2
- •Document your IP scheme before building the network
- •Use /30 for point-to-point links between routers to conserve addresses
- •Avoid overlapping subnets when connecting multiple networks
- •Many networks use 10.0.0.0/8 internally - this provides ample address space
- •Save your /30s for router point-to-point links rather than wasting /24s