IP/Subnet Calculator
DeveloperCalculate subnet details, CIDR notation, network ranges, and available hosts from IP addresses.
Network Information
Host Information
Binary Representation
Common Subnet Quick Reference
What is This Tool?
An IP subnet calculator computes network addresses, broadcast addresses, host ranges, and subnet masks from CIDR notation or IP/mask combinations. Supports both IPv4 and IPv6 addressing with detailed binary breakdowns for network planning and troubleshooting.
Subnetting divides networks into smaller segments for security, performance, and address management. A /24 subnet (255.255.255.0) provides 254 usable hosts, while a /16 provides 65,534. Understanding subnetting is essential for network design, firewall rules, and cloud VPC configuration.
Common Use Cases
Network Design
Plan IP address allocation, subnet sizing, and VLAN segmentation for enterprise and cloud networks.
Cloud Infrastructure
Size AWS VPC subnets, Azure VNets, and GCP subnets correctly for your workload requirements.
Firewall Rules
Calculate CIDR ranges for security group rules, ACLs, and firewall allow/deny lists.
Troubleshooting
Verify that IP addresses are within expected subnets when debugging connectivity and routing issues.
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) uses IP/prefix format: 192.168.1.0/24. The prefix length indicates how many bits are the network portion.
How many hosts in a /24?
254 usable hosts (2^8 - 2). The network address and broadcast address are reserved. A /25 gives 126, a /26 gives 62, and so on.
What is the difference between public and private IPs?
Private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) are for internal networks. Public IPs are routable on the internet.