{
  "slug": "barometric-pressure-altitude",
  "title": "Barometric Pressure Altitude Calculator",
  "heading": "Barometric Pressure & Density Altitude Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/barometric-pressure-altitude",
  "summary": "Convert station pressure and temperature into pressure altitude and density altitude.",
  "description": "Pressure altitude and density altitude are critical for pilots, high-altitude athletes, and anyone trying to understand why the same physical elevation performs differently on a hot day versus a cold one. Pressure altitude adjusts your field elevation for non-standard barometric pressure relative to the standard atmosphere (29.92 inHg at sea level), while density altitude further adjusts for temperature — hot air is less dense, so a hot day at a given elevation behaves like a much higher, thinner-air elevation for aircraft performance, engine combustion, and human oxygen availability. This is exactly why aircraft need longer runways on hot summer afternoons at high-elevation airports, and why marathon times at altitude get worse on unusually warm race days.",
  "formula": "Pressure altitude (ft) = (29.92 − station pressure) × 1000 + field elevation. Density altitude ≈ pressure altitude + 120 × (OAT − ISA temp at that altitude).",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=barometric-pressure-altitude",
  "inputs": [
    {
      "id": "elevation",
      "label": "Field elevation",
      "kind": "number",
      "hint": null,
      "default": 5430,
      "unit": "ft",
      "min": -300,
      "max": 15000
    },
    {
      "id": "pressure",
      "label": "Station (altimeter) pressure",
      "kind": "number",
      "hint": null,
      "default": 29.7,
      "unit": "inHg",
      "min": 27,
      "max": 31.5
    },
    {
      "id": "tempF",
      "label": "Outside air temperature",
      "kind": "number",
      "hint": null,
      "default": 90,
      "unit": "°F",
      "min": -30,
      "max": 120
    }
  ],
  "outputs": [
    {
      "id": "densityAlt",
      "label": "Density altitude",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "pressureAlt",
      "label": "Pressure altitude",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "isaTempF",
      "label": "Standard (ISA) temp at this altitude",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "deltaFromIsa",
      "label": "Degrees above/below ISA standard",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Field elevation: 5430 ft",
      "Station (altimeter) pressure: 29.7 inHg",
      "Outside air temperature: 90 °F"
    ],
    "outputs": [
      "Density altitude: 11,786",
      "Pressure altitude: 5,650",
      "Standard (ISA) temp at this altitude: 38.9",
      "Degrees above/below ISA standard: 51.1"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter field elevation (ft).",
      "Enter station (altimeter) pressure (inHg).",
      "Enter outside air temperature (°F).",
      "Read your density altitude on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "elevation": 3260,
        "pressure": 27,
        "tempF": 54
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "elevation": 5430,
        "pressure": 29.7,
        "tempF": 90
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "elevation": 8690,
        "pressure": 31.5,
        "tempF": 120
      }
    }
  ],
  "limitations": [
    "Estimates assume standard, average conditions — local rules, pricing, and materials vary.",
    "Results are rounded for readability; add a buffer before ordering, booking, or committing.",
    "Double-check anything with a real cost attached against a local quote."
  ],
  "faq": [
    {
      "q": "Why do pilots care about density altitude so much?",
      "a": "Engine power, propeller efficiency, and wing lift all depend on actual air density, not indicated elevation. High density altitude (hot day, high elevation, low pressure) means longer takeoff rolls, reduced climb rate, and lower service ceilings — a major factor in high-elevation airport accidents historically."
    },
    {
      "q": "How does this affect human performance at altitude?",
      "a": "Density altitude correlates with available oxygen partial pressure, so a hot day at a mile-high stadium can present the body with effectively higher-altitude conditions than the field elevation suggests, which is part of why altitude training camps and events monitor weather conditions closely, not just fixed elevation."
    },
    {
      "q": "Where do I get current station pressure?",
      "a": "Local ATIS/AWOS broadcasts at airports report current altimeter setting directly; for non-aviation use, most weather apps report 'pressure' either as station pressure or sea-level-adjusted pressure, so make sure you're using the actual local station reading, not the sea-level-corrected value."
    },
    {
      "q": "Why is the density altitude formula only approximate?",
      "a": "The full calculation involves the ideal gas law applied to actual vs. standard atmosphere air density, plus humidity effects (humid air is actually less dense than dry air at the same temperature and pressure). This simplified version captures the dominant temperature effect, accurate to within a few hundred feet for most conditions."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/wind-pressure-on-wall",
    "https://www.revenuelab.fyi/toolbox/heat-index-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Barometric Pressure Altitude Calculator (https://www.revenuelab.fyi/toolbox/barometric-pressure-altitude)"
}