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IPv4 Range Expander

Expand an IPv4 CIDR range into a list of individual IP addresses. Calculate network, broadcast, and host count. Runs entirely in your browser.

Local processing

What is IPv4 Range Expander?

CIDR notation compactly represents a range of IP addresses. The prefix length (e.g., /24) determines how many addresses are in the range: 2^(32-prefix) addresses.

How It Works

The tool parses the CIDR, computes the network mask, network address, and broadcast address, then enumerates all host IPs. Ranges over 1024 addresses are summarized with count and first/last IPs.

Common Use Cases

  • Listing all IPs in a subnet
  • Verifying network boundaries
  • Planning IP allocations

Technical Details

CIDR: RFC 4632. Prefix range: /0 to /32. Host count: 2^(32-prefix) - 2 (excluding network and broadcast) for /31 and below.

How to Use

  1. Enter a CIDR range (e.g., 192.168.1.0/30)
  2. Click Expand
  3. View the IP list and network details

Privacy

All processing happens in your browser. Your data is never uploaded to any server.

FAQ

What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation specifies an IP range as address/prefix, e.g., 192.168.1.0/24 covers 256 addresses.

Is there a limit on expansion?

Yes, ranges larger than 1024 IPs are summarized rather than fully listed to prevent browser performance issues.

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