Subnet Calculator

Calculate subnet masks, network addresses, broadcast addresses, and usable IP ranges. Free online IPv4 subnet calculator.

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📖 CIDR Reference

CIDR = Classless Inter-Domain Routing
Format: IP_ADDRESS/PREFIX
Example: 192.168.1.0/24

/8255.0.0.016,777,214 hosts
/16255.255.0.065,534 hosts
/24255.255.255.0254 hosts
/25255.255.255.128126 hosts
/26255.255.255.19262 hosts
/27255.255.255.22430 hosts
/28255.255.255.24014 hosts
/29255.255.255.2486 hosts
/30255.255.255.2522 hosts
/32255.255.255.2551 host

🔒 Private IP Ranges (RFC 1918)

  • Class A: 10.0.0.0/8
  • Class B: 172.16.0.0/12
  • Class C: 192.168.0.0/16