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Calculate Altitude from Pressure

Barometric Formula:

\[ h = \frac{R \times T}{g} \times \ln\left(\frac{P_0}{P}\right) \]

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Pa
Pa

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1. What is the Barometric Formula?

Definition: This calculator estimates altitude based on atmospheric pressure using the barometric formula, which relates pressure to height in an isothermal atmosphere.

Purpose: It's used in aviation, meteorology, and altitude measurements when direct altitude measurement isn't available.

2. How Does the Calculator Work?

The calculator uses the barometric formula:

\[ h = \frac{R \times T}{g} \times \ln\left(\frac{P_0}{P}\right) \]

Where:

Explanation: The formula calculates the altitude where the pressure would be P, given a sea-level pressure P₀ and constant temperature T.

3. Importance of Pressure-Altitude Calculation

Details: Accurate altitude measurement is crucial for aviation safety, weather forecasting, and scientific research.

4. Using the Calculator

Tips: Enter temperature in Kelvin (default 288.15K ≈ 15°C), sea level pressure in Pascals (default 101325 Pa = 1 atm), and current pressure in Pascals. Current pressure must be less than sea level pressure.

5. Frequently Asked Questions (FAQ)

Q1: Why use Kelvin for temperature?
A: The gas law requires absolute temperature. Kelvin is the SI unit for thermodynamic temperature.

Q2: What's a typical sea level pressure?
A: Standard atmospheric pressure is 101325 Pa (1 atmosphere), but actual pressure varies with weather conditions.

Q3: How accurate is this formula?
A: It assumes constant temperature (isothermal atmosphere). For more accuracy, use the International Standard Atmosphere model.

Q4: Can I use hPa or mmHg instead of Pascals?
A: Yes, but convert to Pascals first (1 hPa = 100 Pa, 1 mmHg ≈ 133.322 Pa).

Q5: What's the maximum altitude this can calculate?
A: The formula works best below 11 km (tropopause). Above that, temperature isn't constant.

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