Subnet Overlap Detector

Paste a list of CIDR blocks to detect overlaps and find unused IP gaps between them. Useful for network planning, audit, and IP address management before deploying to AWS VPC, Azure VNet, or on-premise routers.

One CIDR per line, comma-separated, or semicolon-separated

How It Works

  1. Parse each CIDR — convert to 32-bit integer start/end range.
  2. O(n²) pairwise comparison — detect any overlapping ranges.
  3. Severity grading — critical (full containment), high (>50% overlap), medium (partial).
  4. Gap analysis — sort ranges by start IP and identify unused address space between them.