IP Subnet Calculator
Calculate subnet masks, network ranges, usable host ranges, and CIDR notation for IPv4 networks. Fast, accurate client-side calculations for network administration.
Worked Example
Calculate the subnet information for 192.168.1.0/24 (common home/office network):
IP Address: 192.168.1.0
CIDR Notation: /24
Subnet Mask: 255.255.255.0
Network Address: 192.168.1.0
Broadcast: 192.168.1.255
Usable Range: 192.168.1.1 to 192.168.1.254 (254 hosts)
Subnet Calculation Formula
Total Hosts = 2^(32 - CIDR); Usable Hosts = Total Hosts - 2; Network Address = IP AND Subnet Mask; Broadcast = Network OR Wildcard
The IP subnet calculator breaks down an IPv4 address and subnet mask to determine network boundaries, usable host ranges, and total capacity. It converts between CIDR notation and dotted-decimal subnet masks, calculates the network and broadcast addresses, and provides the wildcard mask used in firewall rules.
Frequently Asked Questions
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When to Use the IP Subnet Calculator
This calculator is essential for network administrators, IT professionals, and anyone designing or managing IP networks:
- Network Planning: Determine appropriate subnet sizes for your organization's growing network needs and IP address allocation strategies.
- VLAN Design: Calculate subnet ranges for virtual local area networks to segment traffic and improve network security and performance.
- Firewall Rules: Generate subnet masks and wildcard masks needed for access control lists (ACLs) and firewall configurations.
- Office IP Allocation: Plan IP address distribution for office locations, ensuring each site has sufficient addresses for devices and growth.
- Data Center Networking: Design efficient subnetting for servers, storage, and backup systems in data center environments.
- Network Troubleshooting: Quickly verify IP addresses, subnet masks, and network boundaries when diagnosing connectivity issues.
Common Use Cases
Common Subnet Sizes Reference
| CIDR | Subnet Mask | Wildcard Mask | Total Hosts | Usable Hosts |
|---|---|---|---|---|
| /24 | 255.255.255.0 | 0.0.0.255 | 256 | 254 |
| /25 | 255.255.255.128 | 0.0.0.127 | 128 | 126 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,536 | 65,534 |
| /8 | 255.0.0.0 | 0.255.255.255 | 16,777,216 | 16,777,214 |
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