Calculate IPv4/IPv6 subnets and CIDR
Subnet Calculator is an essential network planning tool that calculates IPv4 subnets, CIDR notation, network addresses, broadcast addresses, and usable host ranges for efficient IP address allocation. Subnetting is the practice of dividing a network into smaller sub-networks to improve security, reduce broadcast traffic, and organize network infrastructure logically. This calculator helps network administrators, system engineers, and IT professionals plan IP address schemes, configure routers and switches, and troubleshoot network connectivity issues. The tool accepts IP addresses in standard dotted-decimal notation (like 192.168.1.1) and subnet masks in either traditional format (255.255.255.0) or CIDR notation (/24). CIDR (Classless Inter-Domain Routing) is the modern standard for IP addressing that uses a suffix number to indicate how many bits are used for the network portion. Understanding subnetting is crucial for network design because it determines how many devices can connect to each network segment, how networks are isolated from each other, and how routing tables are configured. The calculator shows the network address (first IP in the range), broadcast address (last IP in the range), first usable host IP, last usable host IP, total number of addresses, and number of usable host addresses. This subnet tool is invaluable for network engineers designing enterprise networks, cloud architects planning VPC configurations, system administrators configuring DHCP scopes, and students learning networking fundamentals.