IP Subnet Calculator
Calculate subnet masks, network addresses, broadcast addresses, and IP ranges. Essential tool for network administrators and IT professionals.
Subnet Calculator
Enter IP address and subnet information
Subnet Results
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to see subnet information
CIDR Reference
Network Summary
IP Address Breakdown
Binary Representation
Address Ranges
Subnet Details
Network Properties
Usable IP Range
Subnetting Information
CIDR Reference Chart
Subnetting Best Practices
Network Administration Resources
Network Segmentation
Subnetting improves network performance by reducing broadcast domains and organizing devices logically.
Security
Proper subnetting enhances security by isolating network segments and controlling traffic between them.
Performance
Smaller broadcast domains reduce network congestion and improve overall network performance.
Organization
Logical grouping of devices by department, function, or location simplifies network management.
Subnetting FAQs
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents an IP address and its associated routing prefix. It's written as IP_address/prefix_length, where prefix_length is the number of bits in the subnet mask (e.g., 192.168.1.0/24).
How do I calculate the number of usable hosts?
Usable hosts = 2^(32 - CIDR) - 2. Subtract 2 because the network address and broadcast address cannot be assigned to hosts. For example, /24 gives 2^8 - 2 = 254 usable hosts.
What's the difference between network address and broadcast address?
The network address is the first address in a subnet and identifies the network itself. The broadcast address is the last address and is used to send data to all devices on the subnet. Neither can be assigned to individual devices.
When should I use different subnet masks?
Use larger subnets (/24, /25) for user segments with many devices. Use smaller subnets (/30, /31) for point-to-point links. Medium subnets (/26-/29) work well for server segments or smaller departments.
What is VLSM (Variable Length Subnet Masking)?
VLSM allows using different subnet masks within the same network address space. This enables more efficient IP address allocation by creating subnets of different sizes based on actual host requirements.