How to Calculate Altitude from Pressure (ft)

Altitude Formula:

\[ h = 145442 \times \left(1 - \left(\frac{P}{1013.25}\right)^{0.19026}\right) \]

Altitude (ft):

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1. What is the Altitude from Pressure Calculator?

Definition: This calculator estimates altitude in feet based on atmospheric pressure using the barometric formula.

Purpose: It helps pilots, meteorologists, and outdoor enthusiasts determine elevation when pressure measurements are available.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ h = 145442 \times \left(1 - \left(\frac{P}{1013.25}\right)^{0.19026}\right) \]

Where:

\( h \) — Altitude (feet)
\( P \) — Atmospheric pressure (hPa)
1013.25 — Standard sea level pressure (hPa)
145442, 0.19026 — Constants for the barometric formula

Explanation: The formula relates atmospheric pressure to altitude in the International Standard Atmosphere (ISA) model.

3. Importance of Altitude Calculation

Details: Accurate altitude determination is crucial for aviation, weather forecasting, and navigation in mountainous terrain.

4. Using the Calculator

Tips: Enter the atmospheric pressure in hectopascals (hPa). The value must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the standard sea level pressure?
A: 1013.25 hPa (or 29.92 inHg) is the standard atmospheric pressure at sea level.

Q2: How accurate is this calculation?
A: It provides a good estimate under standard conditions but may vary with temperature and weather patterns.

Q3: Can I use this for high-altitude calculations?
A: Yes, it works up to about 36,000 feet (the tropopause).

Q4: What if my pressure is in other units?
A: Convert to hPa first (1 hPa = 1 mbar, 1 inHg = 33.8639 hPa).

Q5: Why does altitude increase as pressure decreases?
A: Atmospheric pressure decreases with height as there's less air above pushing down.