CIDR / Subnet Calculator — Free Online Tool
Enter any IPv4 CIDR notation (e.g. 192.168.1.0/24) to see full subnet details: network address, broadcast address, first/last host, subnet mask, wildcard mask, total and usable hosts, IP class, and private/public status.
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How to use CIDR / Subnet Calculator
- Enter an IP address with CIDR prefix (e.g. 10.0.0.0/16).
- All subnet details appear instantly.
- Use preset buttons for common configurations.
- Copy any value with its Copy button.
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents an IP address and subnet mask together. 192.168.1.0/24 means the network uses 24 bits for the network portion, leaving 8 bits for hosts (256 addresses).
What is the difference between total and usable hosts?
The network address (first) and broadcast address (last) cannot be assigned to hosts. Usable hosts = total − 2.
What is a wildcard mask?
The inverse of the subnet mask. Used in access control lists (ACLs) on routers and firewalls.
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