Calculate subnet

Calculate IPv4 network, broadcast, usable range, and host count from CIDR.

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ToolSubnet Calculator
Input
Output
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Preview

How it works

An address and prefix become 32-bit values. Masking derives network and broadcast, and conventional IPv4 rules derive first and last usable addresses and wildcard mask.

  • CIDR defines the boundary.
  • Usable counts exclude special addresses on traditional subnets.

Worked example

Calculate subnet for 192.168.1.0/24
Get network, broadcast, host range, mask, class, and binary for a /24 subnet
Input
											192.168.1.0/24
Output
												Network address: 192.168.1.0
Broadcast address: 192.168.1.255
Subnet mask: 255.255.255.0
Wildcard mask: 0.0.0.255
CIDR: 24
First host: 192.168.1.1
Last host: 192.168.1.254
Total hosts: 256
Usable hosts: 254
IP class: C
Is private: yes
Binary mask: 11111111.11111111.11111111.00000000
IP binary: 11000000.10101000.00000001.00000000

When to use this

VLAN planning, firewall summaries, and IPAM allocation calculate subnets.

Edge cases

  • /31 point-to-point networks have special host rules.
  • /32 represents one address without a conventional host range.
  • IPv6 has no IPv4 broadcast and needs separate logic.

References