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IPv4 Enclosing CIDR
Find the single smallest IPv4 CIDR block that contains every address and block in a list, and see how much of it is wasted.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
How it works
Unlike aggregation (which can return several blocks), this returns exactly one CIDR — the tightest single block spanning from the lowest to the highest address in the list. The waste figure is that block's size minus the addresses the inputs actually cover, so you can judge whether one block is efficient enough or aggregation into several blocks is better. Bare addresses count as /32. Up to 5,000 entries.