Free Online CIDR Overlap Checker
Check IPv4 CIDR ranges for overlaps, duplicates, address counts, and sorted network boundaries before updating firewall or VPN rules. This tool runs locally in your browser with no upload to a server.
CIDR Overlap Checker
Check IPv4 CIDR ranges for overlaps, duplicates, address counts, and sorted network boundaries before updating firewall or VPN rules.
Or paste manually below. Files are processed in your browser and are not uploaded.
Results will appear here.