# Subnet Calculator — REST API endpoint `subnet-calculator`

Return the full IPv4 subnet breakdown for an address: network and broadcast address, subnet mask, wildcard mask, binary mask, first and last usable host, total and usable host counts, IP class (A-E), and IP type (public, private, loopback, link-local, multicast, reserved). Accepts CIDR notation (192.168.1.0/24), a bare IP (defaults to /24), or an IP plus a dotted subnet mask.

- Category: network
- MCP server: https://mcp.findutils.com/ (Streamable HTTP, no API keys, 120 req/min per IP)
- REST endpoint: POST https://api.findutils.com/api/tools/subnet-calculator/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/api/subnet-calculator/
- Same tool on the other surface: https://findutils.com/mcp/subnet-calculator/

## Call the endpoint (verified example)

```bash
curl -X POST https://api.findutils.com/api/tools/subnet-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "ip": "192.168.1.0/24"
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/subnet-calculator
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `ip` | string | yes | IPv4 address, with or without a /prefix, e.g. "192.168.1.0/24" or "10.0.0.5". Without a prefix /24 is assumed unless mask is given. |
| `mask` | string | no | Optional dotted subnet mask such as "255.255.255.0". When given it overrides the prefix in ip. |

Example arguments (verified):

```json
{
  "ip": "192.168.1.0/24"
}
```

OpenAPI 3.1 spec: https://findutils.com/api/openapi.json · Interactive docs: https://findutils.com/api/docs/

## Also an MCP tool

```bash
claude mcp add findutils --transport http https://mcp.findutils.com/
```

Then ask the client to call `findutils:subnet_calculator`. Full MCP reference: https://findutils.com/mcp/subnet-calculator/

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