Network Calculator

Calculate IP subnets, CIDR notation, and network addresses

Network Parameters
Enter IP address and subnet information
Network Information
Calculated network details and analysis

Enter IP address and subnet to calculate network information

Common Subnet Masks
Click to quickly apply common subnet configurations

/24

255.255.255.0

254 hosts - Standard Class C

/25

255.255.255.128

126 hosts - Half Class C

/26

255.255.255.192

62 hosts - Quarter Class C

/27

255.255.255.224

30 hosts - Small subnet

/28

255.255.255.240

14 hosts - Very small subnet

/30

255.255.255.252

2 hosts - Point-to-point link

Network Examples
Click to load common network configurations

Home Network

Typical home router setup

192.168.1.100/24

Small Office

Small office with 126 hosts

192.168.10.50/25

Corporate LAN

Large corporate network

10.0.1.100/16

DMZ Network

Demilitarized zone with 14 hosts

172.16.1.10/28

Point-to-Point

Router-to-router link

10.1.1.1/30

IP Networking Concepts

CIDR Notation

Classless Inter-Domain Routing (CIDR) uses /n notation where n is the number of network bits.

  • • /24 = 255.255.255.0 (256 addresses, 254 usable)
  • • /25 = 255.255.255.128 (128 addresses, 126 usable)
  • • /30 = 255.255.255.252 (4 addresses, 2 usable)

Private Networks

RFC 1918 defines private IP address ranges for internal networks.

  • • 10.0.0.0/8 (Class A private)
  • • 172.16.0.0/12 (Class B private)
  • • 192.168.0.0/16 (Class C private)