How to Use the IP Subnet Calculator
- Enter a valid IPv4 address.
- Select or enter the CIDR prefix (e.g. /24).
- Click the Calculate button.
- View subnet details including network address, broadcast address, subnet mask, host range, and usable hosts.
What Is IP Subnetting?
IP subnetting is the process of dividing a large network into smaller subnetworks (subnets). It helps organizations manage IP addresses more efficiently, improve security, and reduce unnecessary network traffic.
Network administrators use subnetting to organize devices into logical groups while conserving IP address space.
Understanding CIDR Notation
CIDR (Classless Inter-Domain Routing) notation indicates how many bits are allocated to the network portion of an IP address.
| CIDR | Subnet Mask | Total Addresses | Usable Hosts |
|---|---|---|---|
| /24 | 255.255.255.0 | 256 | 254 |
| /25 | 255.255.255.128 | 128 | 126 |
| /26 | 255.255.255.192 | 64 | 62 |
| /27 | 255.255.255.224 | 32 | 30 |
| /28 | 255.255.255.240 | 16 | 14 |
Information Calculated
- Network Address
- Broadcast Address
- Subnet Mask
- Wildcard Mask
- CIDR Prefix Length
- Total IP Addresses
- Usable Host Addresses
- First Host Address
- Last Host Address
- Binary Representation
Benefits of Subnetting
- Improves network performance
- Reduces broadcast traffic
- Enhances security
- Efficient IP address allocation
- Simplifies network management
- Supports scalable network design
Common Networking Use Cases
Subnet calculations are commonly used by network engineers, system administrators, cloud architects, cybersecurity professionals, students, and IT support teams when planning and managing networks.