# Aviation Density Altitude Calculator

> Aviation Density Altitude Calculator is a paid API for AI agents from aviation-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Calculates density altitude (exact and rule-of-thumb) from field elevation, altimeter setting, and outside air temperature, with a performance flag.

## Facts

- Endpoint: GET https://aviation-calc.x402tookit.com/density-altitude?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/aviation-density-altitude-calculator-661de54e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CfIXWfyFo3U77wGeDhjrb

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 aviation-density-altitude-calculator-661de54e
```

Example prompt: What's the density altitude at a field elevation of 5,500 feet with an altimeter setting of 29.85 inHg and an outside air temperature of 32°C? Give me both the exact value and the rule-of-thumb result, and let me know if performance is a concern.

## When to prefer this

Use this endpoint when you need a rigorous, aviation-standard density altitude computation — including both exact ISA-based calculation and the pilot rule-of-thumb estimate — along with a performance flag indicating whether density altitude is operationally significant. Prefer this over manual calculation or generic atmospheric tools when flight safety or aircraft performance planning is involved.

## Known failure modes

- Missing required parameters (elevationFt, altimeter, oatC) returns an error
- Out-of-range values (e.g. elevation below -1500 ft or above 30000 ft, OAT outside -60 to 60°C) may return a validation error or degraded result
- Invalid altimeter unit specification may cause incorrect conversion
- Payment not included or insufficient USDC triggers 402 payment required response

## How this service works

Density altitude from field elevation, altimeter setting and temperature, exact and by rule of thumb, with a performance flag.

## Output

Returns exact density altitude in feet, rule-of-thumb density altitude in feet, pressure altitude, station pressure in hPa, air density in kg/m³, density ratio, ISA deviation and ISA temperature at pressure altitude, density altitude above field, plus a human-readable summary, verdict/performance flag, degraded flag, disclaimer, and a list of reasons behind the assessment.

## 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": [
      "elevationFt",
      "altimeter",
      "oatC"
     ],
     "properties": {
      "oatC": {
       "type": "number",
       "description": "Outside air temperature in C, -60 to 60"
      },
      "unit": {
       "type": "string",
       "description": "inhg (default) or hpa"
      },
      "altimeter": {
       "type": "number",
       "description": "Altimeter setting: inHg like 29.92 or hPa like 1013"
      },
      "elevationFt": {
       "type": "number",
       "description": "Field elevation in feet, -1500 to 30000"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "oatC": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "elevationFt": {
       "type": [
        "null",
        "number"
       ]
      },
      "densityRatio": {
       "type": [
        "null",
        "number"
       ]
      },
      "isaDeviationC": {
       "type": [
        "null",
        "number"
       ]
      },
      "airDensityKgM3": {
       "type": [
        "null",
        "number"
       ]
      },
      "density
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aviation-density-altitude-calculator-661de54e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from aviation-calc.x402tookit.com](https://www.zero.xyz/host/aviation-calc.x402tookit.com/llms.txt)