# Network Calc IPv6 Prefix Calculator

> Network Calc IPv6 Prefix Calculator is a paid API for AI agents from network-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates first/last address, size, /64 count, nth subnet, address type, and reverse DNS zone for an IPv6 CIDR prefix.

## Facts

- Endpoint: GET https://network-calc.x402tookit.com/cidr-ipv6?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/network-calc-ipv6-prefix-calculator-b71d06a8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nIDDWnhKHS-QJY_bbMlDe

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability network-calc-ipv6-prefix-calculator-b71d06a8
```

Example prompt: What's the first and last address, total size, number of /64 subnets, and reverse DNS zone for the IPv6 prefix 2001:db8:abcd::/48?

## When to prefer this

Use this endpoint when you need detailed IPv6-specific prefix analysis — especially /64 and /48 subnet counts, address type classification, or reverse DNS zone generation. Prefer this over a generic CIDR comparison or IPv4 subnet tool when working exclusively with IPv6. Ideal for network automation, ISP provisioning, and DNS infrastructure tasks.

## Known failure modes

- Invalid IPv6 prefix format returns an error or degraded response
- Host bits set in the address (e.g. 2001:db8::1/48) triggers a warning via hostBitsSet flag
- subnetPrefix smaller than or equal to the input prefix length returns an error
- index out of range for the given subnet carve returns an error or empty subnet object
- Non-IPv6 input (e.g. IPv4 CIDR) likely returns an error or unsupported response

## How this service works

IPv6 prefix calculator: first and last address, size, number of /64s, the nth subnet, address type and reverse DNS zone.

## Output

Returns the canonical CIDR, first and last addresses (both compressed and expanded), total address count, number of /64 and /48 subnets, prefix length, netmask, address type classification, reverse DNS zone string, and optionally details of the nth carved subnet including its own first/last addresses and total subnet count.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "cidr"
     ],
     "properties": {
      "cidr": {
       "type": "string",
       "description": "IPv6 prefix, for example 2001:db8:abcd::/48"
      },
      "index": {
       "type": "string",
       "description": "Zero-based number of the subnet to show (with subnetPrefix, default 0)"
      },
      "subnetPrefix": {
       "type": "integer",
       "description": "Prefix length of subnets to carve (greater than the prefix, up to 128)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "cidr": {
       "type": [
        "null",
        "string"
       ]
      },
      "last": {
       "type": [
        "null",
        "string"
       ]
      },
      "first": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "subnet": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "cidr": {
         "type": [
          "null",
          "string"
         ]
        },
        "last": {
         "type": [
          "null",
          "string"
         ]
        },
        "first": {
         "type": [
          "null",
          "string"
         ]
        },
        "index": {
         "type": [
          "null",
          "string"
         ]
        },
        "totalSubnets": {
         "type": [
          "null",
          "string"
         ]
        }
       }
      },
      "netmask": {
       "type": [
        "null",
        "string"
       ]
      },
      "network": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summa
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/network-calc-ipv6-prefix-calculator-b71d06a8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from network-calc.x402tookit.com](https://www.zero.xyz/host/network-calc.x402tookit.com/llms.txt)