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CIDR Overlap and Gap Checker

Pairwise overlaps and uncovered gaps over pasted CIDR blocks.
ClearCIDR blocks

Exact BigInt math over the shared ip-core: pairwise overlaps (identical / contains / partial), gaps between consecutive blocks, adjacency counts.
Nothing in yet

Paste, drop, or type to begin. Everything stays on this device.

Next door in Network

- IPv4 subnet calculator (/network/ipv4-subnet)
- Subnet split & aggregate (/network/subnet-split)
All network tools (/network)

Canonical HTML: https://nutter.tools/network/cidr-check
Markdown version: https://nutter.tools/network/cidr-check/index.md
Plain-text version: https://nutter.tools/network/cidr-check/index.txt
Agent index: https://nutter.tools/llms.txt