🌐 IP Subnet Range Calculator
Calculate network address, broadcast address, usable host range, subnet mask, and CIDR for any IPv4 network. Perfect for network engineers, IT professionals, and students learning subnetting.
Private Class A
10.0.0.0/8
16.7M hosts
Private Class B
172.16.0.0/12
1M hosts
Private Class C
192.168.0.0/16
65K hosts
Point-to-Point
/30 Network
2 usable hosts
IP Subnet Calculator
Enter IPv4 address and select CIDR mask
Binary Representation
Subnet Quick Reference Table
| CIDR | Subnet Mask | Total Hosts | Usable Hosts | Binary Mask |
|---|---|---|---|---|
| /24 | 255.255.255.0 | 256 | 254 | 11111111.11111111.11111111.00000000 |
| /25 | 255.255.255.128 | 128 | 126 | 11111111.11111111.11111111.10000000 |
| /26 | 255.255.255.192 | 64 | 62 | 11111111.11111111.11111111.11000000 |
| /27 | 255.255.255.224 | 32 | 30 | 11111111.11111111.11111111.11100000 |
| /28 | 255.255.255.240 | 16 | 14 | 11111111.11111111.11111111.11110000 |
| /29 | 255.255.255.248 | 8 | 6 | 11111111.11111111.11111111.11111000 |
| /30 | 255.255.255.252 | 4 | 2 | 11111111.11111111.11111111.11111100 |
Private IP Ranges
- Class A:10.0.0.0 - 10.255.255.255 (/8)
- Class B:172.16.0.0 - 172.31.255.255 (/12)
- Class C:192.168.0.0 - 192.168.255.255 (/16)
- Localhost:127.0.0.0 - 127.255.255.255
Special Addresses
- Network Address:First IP (all host bits 0)
- Broadcast Address:Last IP (all host bits 1)
- Default Gateway:Usually first usable host
- APIPA Range:169.254.0.0/16
📚 Understanding IP Subnetting
🔹 Network Address
First IP in subnet where all host bits are 0. Cannot be assigned to hosts. Used to identify the network itself.
🔹 Broadcast Address
Last IP where all host bits are 1. Sends data to all hosts in subnet. Cannot be assigned to hosts.
🔹 Usable Host Range
IPs between network and broadcast addresses. Can be assigned to devices like computers, phones, printers.
📝 Common Subnetting Examples
- Home network (/24): 192.168.1.0 - 254 usable hosts
- Point-to-point link (/30): 4 total IPs, 2 usable - perfect for router connections
- Small office (/29): 8 total IPs, 6 usable - enough for small network
- Large enterprise (/16): 65,534 usable hosts - Class B private network
❓ Frequently Asked Questions
What is a subnet mask?
A subnet mask is a 32-bit number that divides an IP address into network and host portions. It tells devices which part of the IP is the network ID and which part can be assigned to hosts. For example, 255.255.255.0 means first 24 bits are network, last 8 bits are hosts.
How do I calculate usable hosts?
Usable hosts = 2^(32 - CIDR) - 2. The "-2" subtracts network and broadcast addresses. For /24: 2^8 - 2 = 254 usable hosts. For /30: 2^2 - 2 = 2 usable hosts.
What's the difference between public and private IPs?
Private IPs (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) are used internally within networks and not routable on the internet. Public IPs are globally unique and accessible from anywhere on the internet.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation like 192.168.1.0/24 shows the IP address followed by the number of network bits. /24 means 24 bits for network, 8 bits for hosts. It's a modern way to define subnets without traditional class boundaries.