Density Altitude

{
  "airDensityKgM3": 0.9688,
  "asOf": "2026-10-11T14:44:07.798Z",
  "degraded": false,
  "densityAltitudeAboveFieldFt": 2802.1,
  "densityAltitudeFt": 7802.1,
  "densityAltitudeRuleOfThumbFt": 7990,
  "densityRatio": 0.7908,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "elevationFt": 5000,
  "isaDeviationC": 24.91,
  "isaTemperatureAtPressureAltitudeC": 5.09,
  "notChecked": [
    "humidity: moist air is lighter, adding a few hundred feet to density altitude on a humid hot day",
    "the aircraft's actual performance: use the flight manual's charts with this density altitude, not a percentage rule",
    "…2 more"
  ],
  "oatC": 30,
  "pressureAltitudeFt": 5001.1,
  "reasons": [
    "Density altitude is the altitude in the standard atmosphere that has the air's actual density: the aircraft performs as if it were that high.",
    "The rule of thumb (pressure altitude + 120 ft per degree C above ISA) gives 7990 ft.",
    "…1 more"
  ],
  "source": "computed locally",
  "stationPressureHpa": 843.04,
  "summary": "Density altitude 7802 ft at a 5000 ft field (2802 ft above it): pressure altitude 5001 ft, ISA 5.1 C, actual 30 C (ISA +24.9); air density 79.1% of sea level.",
  "verdict": "DENSITY_ALTITUDE_ELEVATED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://aviation-calc.x402tookit.com/density-altitude?altimeter=29.92&elevationFt=5000&oatC=30&unit=inhg'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://aviation-calc.x402tookit.com/density-altitude?altimeter=29.92&elevationFt=5000&oatC=30&unit=inhg' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Faviation-calc.x402tookit.com%2Fdensity-altitude
const res = await pay("https://aviation-calc.x402tookit.com/density-altitude?altimeter=29.92&elevationFt=5000&oatC=30&unit=inhg");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://aviation-calc.x402tookit.com/density-altitude?altimeter=29.92&elevationFt=5000&oatC=30&unit=inhg")
    print(res.status_code, res.text)