# Aviation Pressure Altitude Calculator

> Aviation Pressure 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 pressure altitude from field elevation and altimeter setting (inHg or hPa), returning both the exact ISA result and the 1000 ft/inHg rule-of-thumb approximation.

## Facts

- Endpoint: GET https://aviation-calc.x402tookit.com/pressure-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-pressure-altitude-calculator-af935b6a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wddhY9m2hYYCHnx9SomKK

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-pressure-altitude-calculator-af935b6a
```

Example prompt: What's the pressure altitude at an airport with a field elevation of 3500 feet and an altimeter setting of 29.65 inHg? I want both the exact ISA result and the rule-of-thumb estimate.

## When to prefer this

Choose this endpoint when you need a quick, accurate pressure altitude computation for aviation pre-flight planning, aircraft performance charts, or student pilot instruction — especially when you want both the precise ISA-formula result and the 1000 ft/inHg rule-of-thumb in a single call. It is ideal for automation pipelines that ingest live METAR altimeter settings and field elevations to feed into downstream performance calculations.

## Known failure modes

- Missing required query parameters (elevationFt or altimeter) returns an error
- Elevation outside the valid range (-1500 to 30000 ft) may produce an error or unexpected result
- Invalid unit string (not 'inhg' or 'hpa') may default to inHg or return an error
- Altimeter value inconsistent with the specified unit (e.g. passing 1013 when unit is inhg) will yield a nonsensical result
- Network or payment authorization failure returns a 402 or 5xx error

## How this service works

Pressure altitude from field elevation and altimeter setting (inHg or hPa), exact ISA result and the 1000 ft per inHg rule.

## Output

Returns the computed pressure altitude in feet using the exact ISA formula, along with the rule-of-thumb approximation (1000 ft per inHg deviation from 29.92), the difference between pressure altitude and field elevation, and the altimeter setting expressed in both inHg and hPa units. Also includes station pressure in both units.

## 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"
     ],
     "properties": {
      "unit": {
       "type": "string",
       "description": "inhg (default) or hpa"
      },
      "altimeter": {
       "type": "number",
       "description": "Altimeter setting (QNH): inHg like 29.92 or hPa like 1013"
      },
      "elevationFt": {
       "type": "number",
       "description": "Field or aircraft 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"
       ]
      },
      "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"
       ]
      },
      "altimeterHpa": {
       "type": [
        "null",
        "number"
       ]
      },
      "altimeterInHg": {
       "type": [
        "null",
        "number"
       ]
      },
      "pressureAltitudeFt": {
       "type": [
        "null",
        "number"
       ]
      },
      "stationPressureHpa": {
       "type": [
        "null",
        "number"
       ]
      },
      "stationPressureInHg": {
       "type": [
        "null",
        "number"
       ]
      },
      "
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aviation-pressure-altitude-calculator-af935b6a/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)