CIDR Overlap Checker
Enter two CIDR blocks to check whether they overlap, one contains the other, or they are completely disjoint. Essential for VPC planning, firewall auditing, and network merges.
Try these examples
Subnet contained within a larger block
10.0.0.0/16 vs 10.0.1.0/24
Two disjoint /24s in the same /16
10.0.0.0/24 vs 10.0.1.0/24
A /23 that contains a /24
192.168.0.0/23 vs 192.168.1.0/24
RFC 1918 Class B and the AWS default VPC
172.16.0.0/12 vs 172.31.0.0/16
Different RFC 1918 ranges — no overlap
10.0.0.0/8 vs 192.168.1.0/24