zippydevtoolsNetwork and HTTP
CIDR/Subnet Calculator
Calculate network, broadcast, subnet mask, wildcard mask, and usable range for IPv4 CIDR blocks.
Process the input to see the result here.
Calculate a /24 subnet
Input: 192.168.1.0/24
Output: { "cidr": "192.168.1.0/24", "network": "192.168.1.0", "broadcast": "192.168.1.255", "firstUsable": "192.168.1.1", "lastUsable": "192.168.1.254", "subnetMask": "255.255.255.0", "wildcardMask": "0.0.0.255", "totalAddresses": 256, "usableAddresses": 254 }
What is a CIDR calculator for?
It helps review IPv4 ranges used in allowlists, firewalls, VPNs, subnets, and cloud security groups.
Does it support IPv6?
No. This version calculates IPv4 CIDR blocks only.
What is a usable address?
In traditional networks it excludes network and broadcast. For /31 and /32, the tool keeps the special block count.
Can I use it for cloud security groups?
Yes. Use the result to review ranges and masks before applying them in AWS, GCP, Azure, VPNs, or firewalls.
Is the CIDR sent to a server?
No. The calculation runs locally in your browser.