Standard Atmosphere Pressure Calculator

Standard Atmosphere Pressure:

\[ P = 1013.25 \text{ hPa} \]

Pressure at Altitude (hPa):

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1. What is Standard Atmosphere Pressure?

Definition: The standard atmosphere (atm) is a unit of pressure defined as 1013.25 hPa, equivalent to the average atmospheric pressure at sea level.

Purpose: This calculator helps determine atmospheric pressure at different altitudes, useful for aviation, meteorology, and engineering applications.

2. How Does the Calculator Work?

The calculator uses the barometric formula:

\[ P = P_0 \times \left(1 - \frac{L \times h}{T_0 + L \times h}\right)^{\frac{g \times M}{R \times L}} \]

Where:

\( P \) — Pressure at altitude (hPa)
\( P_0 \) — Standard sea level pressure (1013.25 hPa)
\( h \) — Altitude (meters)
\( T_0 \) — Sea level standard temperature (288.15 K)
\( L \) — Temperature lapse rate (0.0065 K/m)
\( g \) — Gravitational acceleration (9.80665 m/s²)
\( M \) — Molar mass of Earth's air (0.0289644 kg/mol)
\( R \) — Universal gas constant (8.31446 J/(mol·K))

Simplified: The calculator provides a practical approximation of this formula.

3. Importance of Atmospheric Pressure Calculation

Details: Accurate pressure calculations are essential for aircraft performance, weather forecasting, and scientific experiments.

4. Using the Calculator

Tips: Enter the altitude in meters and current temperature in °C. The calculator will show the estimated pressure at that altitude.

5. Frequently Asked Questions (FAQ)

Q1: What is standard sea level pressure?
A: The internationally accepted standard is 1013.25 hPa (29.92 inHg or 1 atm).

Q2: How does altitude affect pressure?
A: Pressure decreases approximately 1 hPa per 8 meters at low altitudes.

Q3: Why include temperature in the calculation?
A: Warmer air is less dense, affecting the pressure-altitude relationship.

Q4: How accurate is this calculator?
A: It provides reasonable estimates but doesn't account for weather systems or local conditions.

Q5: What's the pressure at Mount Everest's summit?
A: Approximately 337 hPa (about 1/3 of sea level pressure).