What is a Subnet Calculator?

A subnet calculator helps network administrators plan and design IP addressing schemes by calculating important network parameters from CIDR (Classless Inter-Domain Routing) notation. It provides essential information needed for network configuration and management.

Key Features:

• Network Address: The first address in the subnet (cannot be assigned to hosts)
• Subnet Mask: Defines which portion of the IP address is the network vs. host
• Wildcard Mask: Inverse of subnet mask, used in Cisco ACLs and routing protocols
• Broadcast Address: The last address in the subnet (used for broadcast messages)
• Usable Host Range: IP addresses that can be assigned to devices
• Total Hosts: Number of devices that can be connected to the subnet

Common Subnet Sizes:

• /24 (255.255.255.0): 254 usable hosts - common for small networks
• /16 (255.255.0.0): 65,534 usable hosts - medium-sized networks
• /8 (255.0.0.0): 16,777,214 usable hosts - large enterprise networks
• /30 (255.255.255.252): 2 usable hosts - point-to-point links

How to Use the Subnet Calculator

Step 1: Enter an IP address with CIDR notation (e.g., 192.168.1.0/24)
Step 2: Click "Calculate Subnet" to see all network details
Step 3: Review network address, broadcast, and usable host range
Step 4: Use "Copy Results" to save the subnet information

Example Calculation:

Input: 192.168.1.0/24

Results:
Network Address: 192.168.1.0
Subnet Mask: 255.255.255.0
CIDR Notation: /24
Wildcard Mask: 0.0.0.255
Broadcast Address: 192.168.1.255
First Usable Host: 192.168.1.1
Last Usable Host: 192.168.1.254
Total Usable Hosts: 254
    

Related Network Tools

• IP Range Generator - Generate list of IPs from CIDR
• Network Mask Calculator - Convert between mask formats
• IPv4 to IPv6 Converter - Convert IP address formats
• IP Geolocation Lookup - Find location of IP addresses