CIDR to IP Range Calculator

This free CIDR calculator converts IPv4 CIDR notation (for example 192.168.1.0/24) into complete subnet details.

It calculates:

  • Network address
  • Broadcast address
  • Subnet mask
  • Wildcard mask
  • Total IP addresses
  • First usable IP
  • Last usable IP
  • Usable host count

Use it for classic subnet planning, firewall configuration, IP range validation, and networking design.

Enter any IPv4 CIDR (e.g., 192.168.1.0/24) below to calculate network ranges and details.

What This CIDR Calculator Does

CIDR (Classless Inter-Domain Routing) allows flexible subnet sizing by defining how many bits are used for the network portion of an IP address.

Given a CIDR block, this tool:

  • Determines the network address (first address in the subnet)
  • Calculates the broadcast address (last address in the subnet)
  • Converts the prefix to a subnet mask
  • Computes the wildcard mask
  • Calculates the total number of IP addresses
  • Identifies the usable host range

This makes it useful for both beginners learning subnetting and experienced engineers validating IP ranges.

Example: 10.0.0.0/24

CIDR: 10.0.0.0/24

  • Network address: 10.0.0.0
  • Broadcast address: 10.0.0.255
  • Subnet mask: 255.255.255.0
  • Total IP addresses: 256
  • Usable hosts: 254
  • Usable range: 10.0.0.1 – 10.0.0.254

A /24 subnet uses 24 bits for the network portion and leaves 8 bits for hosts, resulting in 256 total IP addresses.

Understanding CIDR Notation

CIDR notation expresses an IP network using:

IP address / prefix length

Example:

  • /16 → 65,536 total addresses
  • /24 → 256 total addresses
  • /30 → 4 total addresses

The prefix length determines how many bits are reserved for the network.
The remaining bits define the host space.

Total addresses are calculated as:

2^(32 - prefix)

Network vs Broadcast Address

In traditional IPv4 subnetting:

  • The network address identifies the subnet itself.
  • The broadcast address is used to send traffic to all hosts within the subnet.
  • These two addresses are typically not assignable to devices.

For example, in 192.168.1.0/24:

  • 192.168.1.0 → network address
  • 192.168.1.255 → broadcast address

All assignable host IPs fall between those values.

When to Use This vs the Cloud Usable IP Calculator

This tool performs classic subnet math.

If you are working in Azure, AWS, or Google Cloud, cloud providers reserve additional IP addresses inside each subnet.

In those cases, use:

→ Cloud Usable IP Calculator

The cloud-aware calculator adjusts for provider-reserved IP addresses automatically.

Frequently Asked Questions

Does this CIDR calculator support IPv6?

Not yet. This tool currently supports IPv4 only. An IPv6 subnet calculator is planned.

What is a wildcard mask?

A wildcard mask is the inverse of a subnet mask. It is commonly used in firewall and ACL configurations.

Can I enter a host IP instead of the network address?

Yes. The calculator automatically normalizes the network based on the prefix.