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/ CIDR Calculator

CIDR to IP Range

CIDR Notation

IP Range to CIDR

Start IP

End IP

Split CIDR into Smaller Subnets

CIDR to Split

New Prefix

Quick Reference

/8 = 16.7M hosts

/16 = 65,534 hosts

/24 = 254 hosts

/28 = 14 hosts

/29 = 6 hosts

/30 = 2 hosts

/31 = 2 hosts*

/32 = 1 host

* /31 is used for point-to-point links (RFC 3021)

/ Selected Tool

CIDR Calculator

Convert between CIDR notation and IP ranges, split subnets

■ 01

What is CIDR?

CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and routing. It replaces the old classful network design and allows for more efficient use of IP address space. CIDR notation uses a suffix i…

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How does it work?

CIDR to Range Converts CIDR notation to the actual IP range. The prefix length determines how many addresses are in the block. A /24 has 256 addresses (2^8), while a /16 has 65,536 addresses (2^16). Range to CIDR Conver…

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Sample Cases

Covers CIDR to Range, Range to CIDR, and Split /24 into /26 so you can compare common inputs and outputs quickly.

/ Code

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/ Integration

Source code from the selected tool, shown here alongside the live version on the right.

/ Source Code

TypeScript

typescript

// No external dependencies needed - pure JavaScript/TypeScript

function ipToNumber(ip: string): number {
  const parts = ip.split('.').map(Number);
  return (parts[0] << 24) + (parts[1] << 16) + (parts[2] << 8) + parts[3];
}

function numberToIp(num: number): string {
  return [
    (num >>> 24) & 255,