OT Subnet Calculator

IP Subnet Calculator combines fast IPv4 calculations with professional network planning and a compact IPAM. Calculate network addresses, broadcasts, host ranges, subnet masks, and CIDR prefixes—or document complete sites, customers, and devices.

FAST AND ACCURATE
• Enter an IPv4 address or CIDR directly
• Network, broadcast, first and last host
• Usable host count and address classification
• Quick selection for common prefixes
• Copy and export results

IPAM FOR YOUR NETWORKS
• Folders and subfolders for sites, customers, or projects
• Networks with CIDR, VLAN, location, status, and notes
• Devices with hostname, IP, and MAC address
• Complete CSV export
• iCloud sync across your devices
• Share your IPAM and collaborate with others

PRO TOOLS
• Overlap checks for conflicting networks
• VLSM and VLAN planning
• CIDR aggregation
• IPv6 explorer and prefix comparison
• Favorites, history, and folders

LEARN AND UNDERSTAND
Bit visualization, step-by-step guides, practical scenarios, interactive examples, a quiz, and a cheatsheet help both beginners and network professionals.

Core calculators are free. IPAM, collaboration, and advanced tools are available permanently with Pro—no subscription.