Subnet CIDR Calculator

Calculate network address, broadcast address, host range, subnet mask, and more from CIDR notation

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Quick Examples

Subnet Details

Enter a CIDR address and click Calculate

What Is CIDR Notation?

CIDR (Classless Inter-Domain Routing) notation specifies an IP address and its subnet prefix length using the format IP/prefix. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for host addresses. This calculator helps network engineers plan and understand IP subnet allocations.

How to Use This Tool

  1. Enter CIDR notation — Type an IP address with prefix length (e.g., 192.168.1.0/24) into the input field.
  2. Click Calculate — The tool computes network address, broadcast address, subnet mask, wildcard mask, total hosts, usable hosts, and host range.
  3. Review details — Results are displayed in grid cards showing each calculated value. Binary representations of the IP and subnet mask are also shown.
  4. Try examples — Click the quick example buttons to load common CIDR notations and see their subnet details.
  5. Use for planning — The calculator helps with network segmentation, VLAN design, and IP address allocation planning.

Frequently Asked Questions

Is my data sent to a server?

No. All processing is performed locally in your browser. Your IP data never leaves your device.

What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation uses the format IP/prefix where the prefix length indicates how many bits represent the network portion. For example, /24 means 24 network bits and 8 host bits.

What is the difference between total hosts and usable hosts?

Total hosts is 2^(32-prefix) for IPv4. Usable hosts subtracts 2 for the network and broadcast addresses, which cannot be assigned to devices.

Can I calculate IPv6 subnets?

This tool currently supports IPv4 subnetting only. IPv6 support may be added in the future.

Is this tool free to use?

Yes. This tool is completely free with no usage limits or registration required.

Last updated: 9 Jul 2026