NetmaskVLSM planner, IPv6, offline

Netmask 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.

WHAT MAKES SUBNETMASKCALCULATOR DIFFERENT

• A VISUALIZER YOU CAN TOUCH
  The binary mask view is not a diagram — tap any bit to move the boundary and watch every result re-derive live. Subnetting becomes something you feel, not something you look up.

• VLSM SPLITTER (PRO)
  Give it one base block and a list of host requirements; it returns right-sized subnets in order — no gaps, no overlaps. The planning step that used to be a spreadsheet afternoon becomes a thirty-second check.

• FULL IPv6, NOT AN AFTERTHOUGHT
  Compressed and expanded address forms, prefix math, total-address counts — the same clean interface handles both families.

• PRIVATE BY ARCHITECTURE
  No accounts, no analytics, no network calls. Every calculation and every saved plan lives on the device only.

PRICING

The core IPv4 and IPv6 calculators are included in the base install. Netmask Pro — the VLSM splitter, range & aggregation tools, unlimited saved history, and CSV export — is available as a monthly subscription, an annual subscription with a 7-day trial, or a one-time lifetime unlock. No ads in any tier.

FEEDBACK

Made by Peter Zhang. Every email at obeliskclubclub@gmail.com is read personally.

Learn more: https://obelisk.club/subnetmaskcalculator

Terms of Use (EULA): https://obelisk.club/subnetmaskcalculator/terms