CIDR Set Calculator: Exact Union, Intersection & Exclusion
Combine, intersect or subtract IPv4 or IPv6 CIDR lists and export exact aligned blocks without silently widening the covered address space.
Enabling local controls…
1. CIDR sets
One CIDR per line; one family (IPv4 or IPv6) per calculation. Combined input: 1 MiB, 1000 CIDRs; each list: 2000 physical lines. Output: 4096 CIDRs, 1 MiB; 1,000,000 operations. Excess rejected, never truncated. Blank lines ignored; blank list is an empty set.
2. Exact set result
Enter CIDR sets, then choose an operation.
How to use this tool
Enter same-family CIDR lists, choose an operation and inspect normalization and exact coverage. Export the complete result, not just a visible preview.
When not to use it
Do not mix IPv4 and IPv6 in one operation. An exact mathematical set does not prove an access policy, route, ownership or a safe supernet.
Read the guide →