# Network Calc TCP Throughput Calculator

> Network Calc TCP Throughput 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 2026-10-30).

Calculates TCP bandwidth-delay product, required window size and scale factor, and throughput limits from both window size and packet loss (Mathis equation)

## Facts

- Endpoint: GET https://network-calc.x402tookit.com/tcp-throughput?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/network-calc-tcp-throughput-calculator-cfdeab0e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aAbFDZmBV1nCteOptEbKV

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-tcp-throughput-calculator-cfdeab0e
```

Example prompt: What TCP window size and scale factor do I need to fully utilize a 1 Gbps link with 80ms RTT and 1460-byte MSS, and what throughput would I get with 0.05% packet loss?

## When to prefer this

Use this endpoint when you need precise TCP performance calculations — BDP, window scaling requirements, or Mathis throughput bounds — for network engineering, tuning TCP buffer sizes, diagnosing WAN underperformance, or capacity planning. Prefer this over generic bandwidth calculators when you specifically need TCP-layer analysis including window scale factors and loss-based Mathis limits rather than simple link-layer bandwidth math.

## Known failure modes

- Missing required rttMs parameter returns a validation error
- Extremely low or zero RTT values may produce degenerate BDP results
- Very high loss percentages (>10%) may yield near-zero Mathis limits with no useful throughput estimate
- Invalid or non-numeric parameter values return schema validation errors
- Parameters outside physically meaningful ranges may produce warnings in the reasons array

## How this service works

TCP bandwidth-delay product, window size and scale factor needed, throughput limits from window and from packet loss (Mathis).

## Output

Returns a structured JSON object containing: the bandwidth-delay product in bytes, KiB, and MiB; recommended window size and scale shift/multiplier to fill the link; window-limited throughput in Mbps and MBps; Mathis equation loss-limited throughput in Mbps; the factor currently limiting throughput (window or loss); number of TCP segments in flight; a human-readable summary and verdict; and any caveats or degraded-mode flags.

## 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": [
      "rttMs"
     ],
     "properties": {
      "rttMs": {
       "type": "number",
       "description": "Round-trip time in milliseconds"
      },
      "mssBytes": {
       "type": "number",
       "description": "Maximum segment size in bytes (default 1460)"
      },
      "lossPercent": {
       "type": "number",
       "description": "Packet loss in percent (for the Mathis limit)"
      },
      "windowBytes": {
       "type": "number",
       "description": "Receive window in bytes (default 65535 without scaling)"
      },
      "bandwidthMbps": {
       "type": "number",
       "description": "Link bandwidth in Mbps (to size the window)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "rttMs": {
       "type": [
        "null",
        "number"
       ]
      },
      "bdpKiB": {
       "type": [
        "null",
        "number"
       ]
      },
      "bdpMiB": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "bdpBytes": {
       "type": [
        "null",
        "number"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "mssBytes": {
       "type": [
        "null",
        "number"
       ]
      },
      "limitedBy": {
       "type": [
        "null",
        "string"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
   
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/network-calc-tcp-throughput-calculator-cfdeab0e/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)