Explore IPv4 and IPv6 ranges, plan subnets, and see exactly where the boundary falls.
Try
NORMALIZED NETWORK
Network bitsHost bits
Drag the boundary to change the prefix.
Binary & hexadecimal explanation +Reverse DNS +
SUBNET DESIGN
Divide cleanly. Recombine safely.
Join sibling networks
CIDR COMPARISON
See overlap at a glance.
ROUTE WORKBENCH
Summarize and match routes.
Collapse adjacent networks without covering unrelated space, then test longest-prefix routing.
VARIABLE-LENGTH SUBNETTING
Fit needs, not guesses.
Enter usable host requirements, largest-first or in any order.
IPv6 SITE PLANNER
From allocation to /64s.
Carve a site allocation into readable, nibble-aware subnet boundaries.
THE JIPCALC STORY
A network tool from the Java era, routed to the modern web.
01 / THEN
Subnetting before the browser grew up
Authored by Ravi K. Damarla, the recovered jafar.com pages describe JIPCalc as a Java 1.1 IP Subnet/Supernet Calculator for Linux, Windows and Solaris. It calculated network and host ranges, subnet masks, CIDR supernets, and hexadecimal representations at a time when interactive browser tools arrived as applets.
The original feature list also documents graphical network, subnet and host bits; copyable subnet tables; host address lists; DNS resolution; and a decimal, octal, binary and hexadecimal base converter.
02 / NOW
The same idea, for both IP families
This preservation rebuild carries the calculator into standard browser technology, adds IPv6, VLSM allocation, route summarization, longest-prefix matching and reverse-DNS guidance, and requires no install or server-side processing.
All calculations happen locally in the browser. Shared URLs encode only the address and prefix you choose.