IP Range to CIDRs

Convert one inclusive IPv4 or IPv6 start/end range into the smallest exact CIDR list, without adding addresses.

Calculated in your browser · No API request

Your IP range

Start IP

First included address. Enter one IPv4 or IPv6 address without a CIDR prefix (up to 64 characters).

End IP

Last included address. Use the same family and an address at or after Start IP (up to 64 characters).

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Exact range result

Your result will appear here

Enter both inclusive endpoints to see their exact CIDR list and address count.

What the result means

Both endpoints are included. The result is the minimal sorted CIDR list covering exactly this range, with no gaps, overlaps, or added addresses. A single covering CIDR can include addresses outside the range. Counts include every address, including IPv4 network and broadcast addresses, and remain exact for large IPv6 ranges.

IPv4

Inclusive range: 203.0.113.11 through 203.0.113.23.

203.0.113.11/32
203.0.113.12/30
203.0.113.16/29

IPv6

Inclusive range: 2001:db8::b through 2001:db8::17.

2001:db8::b/128
2001:db8::c/126
2001:db8::10/125

How does this differ from a single covering CIDR?

This list contains exactly the inclusive range, with no additional addresses. A single covering CIDR can include addresses before the start or after the end. Use exact conversion when an allowlist must match the supplied range.

Can I use equal or reversed endpoints?

Equal endpoints return one host CIDR: /32 for IPv4 or /128 for IPv6. Reversed endpoints are rejected and never silently swapped. Both endpoints must be IP addresses of the same family, without CIDR prefixes.

Which addresses are counted?

Every address between the endpoints counts, including both endpoints and IPv4 network and broadcast addresses. Counts remain exact even across the complete IPv6 address space; addresses are not individually enumerated.

Where do my endpoints go?

Browser calculations stay in memory on your device, without uploads, persistence, logging, or input-bearing URLs. Web API and remote MCP calls send endpoints to the server. This operation is available on the website, Web API, and MCP.

Ask an AI agent to represent one inclusive start/end IP range as its minimal exact CIDR list.

Tool name: range-to-cidrs

Server address: https://api.staging.packetrove.com/mcp

Streamable HTTP · No account or API key required

Pass start and end as IPv4 or IPv6 addresses from the same family, without CIDR prefixes, up to 64 characters each. End must be at or after start.

Example arguments

{
  "start": "203.0.113.11",
  "end": "203.0.113.23"
}

Example result using documentation addresses

{
  "family": "ipv4",
  "range": {
    "first": "203.0.113.11",
    "last": "203.0.113.23"
  },
  "cidrs": [
    "203.0.113.11/32",
    "203.0.113.12/30",
    "203.0.113.16/29"
  ],
  "cidrCount": 3,
  "addressCount": "13"
}

Optional tool page link in successful responses

{
  "type": "resource_link",
  "uri": "https://staging.packetrove.com/range-to-cidrs",
  "name": "range-to-cidrs",
  "title": "IP Range to CIDRs",
  "description": "Browser calculator for exact inclusive IP range conversion and its limits. Opens without your MCP inputs or result.",
  "mimeType": "text/html"
}

Read canonical range.first and range.last, sorted cidrs, cidrCount, and exact decimal-string addressCount. Equal endpoints produce one /32 or /128; a complete address space produces /0. Errors identify the start or end field.

The browser calculates locally. API and remote MCP calls submit endpoints to the server. The tool does not inspect live allocation or change firewall, routing, or VPN configuration. CLI range conversion is not available.

Read the MCP connection guide

IP Range to CIDRs

Your IP range

Exact range result

Your result will appear here

What the result means

IP range examples

Questions about IP range conversion

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