🔢 Classless Inter-Domain Routing (CIDR) Subnet Engine
IPv4 Subnet Calculator
Calculate subnet masks, wildcard masks, usable host IP ranges, broadcast addresses, and binary bitmasks with instant CIDR solving.
Standard Subnet Scenarios:
/24 Standard LAN (254 Hosts)
/16 Medium Enterprise (65,534 Hosts)
/20 Cloud VPC (4,094 Hosts)
/30 Point-to-Point Link (2 Hosts)
Usable Host IP Address Range
192.168.1.1 – 192.168.1.254
Subnet Mask
255.255.255.0
Dotted decimal
Network Address
192.168.1.0
Route ID
Broadcast Address
192.168.1.255
Subnet broadcast
Wildcard Mask (ACL)
0.0.0.255
Cisco inverse mask
32-Bit Binary Bitmask Visualization:
IP Address:
11000000.10101000.00000001.00110010
Subnet Mask:
11111111.11111111.11111111.00000000
Scope & Class:
Class C (Private RFC 1918 Address)
Understanding IPv4 Subnetting & CIDR
In IPv4 networking, a 32-bit address is split into a Network ID and a Host ID using a subnet mask:
- Usable Hosts Formula: $\text{Hosts} = 2^{(32 - \text{CIDR})} - 2$ (excluding the network and broadcast addresses).
- Private Address Spaces (RFC 1918):
10.0.0.0/8(10.0.0.0 – 10.255.255.255)172.16.0.0/12(172.16.0.0 – 172.31.255.255)192.168.0.0/16(192.168.0.0 – 192.168.255.255)