OctetLab: Subnet Calculator

OctetLab is a subnet calculator built for network engineers, sysadmins, and students who need answers in seconds, not spreadsheets. Enter an IPv4 or IPv6 address and instantly see the network address, broadcast address, usable host range, and subnet mask — broken down bit by bit in a visualizer you can tap to reshape the mask boundary by hand. Every calculation runs fully on-device: no accounts, no network calls, no ads. INCLUDED • Instant IPv4 subnet calculator with a tap-to-toggle binary bit visualizer — see and shape the mask boundary directly • Full IPv6 subnet support, including compressed and expanded address forms • Copy any result field or share a full subnet summary in one tap • Save your recent calculations to a running history PRO (ONE-TIME UNLOCK) • VLSM subnet splitter — divide a network into right-sized subnets by host count • Unlimited saved calculation history • Export subnet plans to CSV OctetLab does one job well: turning subnetting math into a clean, tappable interface — no lookup tables, no guesswork. Terms of Use (EULA): https://obelisk.club/subnetmaskcalculator/terms