Inspect IPv4 or IPv6 blocks with exact integer math, test membership and overlap, convert ranges to minimal CIDRs, aggregate route lists, split prefixes, and export clean network plans—all locally.
CIDR prefixes identify a contiguous high-order bit prefix. This tool normalizes host addresses to the containing network before calculations and uses BigInt for IPv6, avoiding floating-point approximations.
IPv6 output follows the RFC 5952 style: lowercase hex, suppressed leading zeroes, and the longest zero run compressed once.
Use this CIDR workbench for ranges, route aggregation, containment and prefix operations. Use Tool #385 when you need IPv4 usable-host semantics, dotted masks, wildcard masks, equal subnetting or VLSM planning.