Atmosphere Conversion Tool - Convert Atmosphere to Any Unit
Convert Atmosphere to Other Units
Quick Conversions
Convert Other Units to Atmosphere
Quick Conversions
Related Pressure / Stress Units
Atmosphere Conversion Table
This comprehensive atmosphere conversion table shows how various units relate to atmospheres. Use this reference for quick conversions between atmospheres and other common pressure units.
| Conversion | To Unit | Multiplier |
|---|---|---|
| Atmosphere to pascals | Pascals | 101325 |
| Atmosphere to kilopascals | Kilopascals | 101.325 |
| Atmosphere to bar | Bar | 1.01325 |
| Atmosphere to millibar | Millibar | 1013.25 |
| Atmosphere to torr | Torr | 760 |
| Atmosphere to psi | Pounds per square inch | 14.6959 |
| Atmosphere to cmH₂O | Centimeters of water | 1033.23 |
| Atmosphere to inHg | Inches of mercury | 29.9213 |
This atmosphere conversion reference table provides accurate conversion factors for common pressure units. All values are based on internationally recognized standards for maximum precision in scientific and engineering applications.
What is an Atmosphere?
The atmosphere (symbol: atm) is a unit of pressure defined as exactly 101325 pascals (Pa). This value represents the average atmospheric pressure at sea level on Earth. The atmosphere is a convenient unit for expressing pressures close to Earth's surface pressure and is widely used in meteorology, engineering, and chemistry.
While not an SI unit, the atmosphere is accepted for use with the SI system. Our atmosphere conversion tool helps you easily convert between atmospheres and other units. For example, 1 atmosphere equals approximately 14.7 pounds per square inch (psi) or 760 torr (mmHg).
What is the SI of Atmosphere?
The atmosphere is not an SI unit, but it is accepted for use with the International System of Units (SI). The SI unit for pressure is the pascal (Pa), which is defined as one newton per square meter (N/m²). All other pressure units in the metric system can be related to the pascal:
- Atmosphere (atm) = 101325 pascals
- Kilopascal (kPa) = 1000 pascals
- Bar = 100000 pascals
- Millibar (mbar) = 100 pascals
What are Atmospheres Used For?
Atmospheres are used in a wide range of applications across science, engineering, and everyday life. As a practical unit for standard atmospheric pressure, atmospheres provide a convenient reference point for pressure measurements:
Meteorology
Weather forecasting and atmospheric pressure measurements. Meteorologists often report barometric pressure in millibars or atmospheres to describe high and low pressure systems that affect weather patterns.
Chemistry & Physics
Gas law calculations and standard conditions. Scientists often use atmospheres when describing the pressure of gases in experiments, especially when comparing to standard temperature and pressure (STP) conditions.
Engineering
Pressure vessel design and fluid dynamics. Engineers use atmospheres when calculating pressure differentials in systems like HVAC, hydraulic systems, and compressed air systems where pressures are close to atmospheric pressure.
Aviation
Flight altitude and cabin pressure calculations. Pilots and aerospace engineers use atmospheres when calculating pressure changes with altitude and determining safe cabin pressures for aircraft at cruising altitudes.
Etymology and History
The term "atmosphere" comes from the Greek words "atmos" (vapor) and "sphaira" (ball or globe), referring to the layer of gases surrounding the Earth. The concept of atmospheric pressure was first demonstrated by Evangelista Torricelli in 1644 with his invention of the mercury barometer.
The standard atmosphere was defined in 1954 by the 10th General Conference on Weights and Measures (CGPM) as exactly 101325 pascals. This definition was chosen to closely match the average atmospheric pressure at sea level, which had been previously measured as approximately 760 millimeters of mercury (mmHg) or torr. The standard atmosphere provides a useful reference point for scientific and engineering calculations involving gases and pressures.
Frequently Asked Questions
Why is the atmosphere used as a pressure unit?
The atmosphere is used as a pressure unit because it represents the average pressure exerted by Earth's atmosphere at sea level. This makes it a convenient reference point for many scientific and engineering applications where pressures are close to this value. Its definition as exactly 101325 pascals ensures precise and consistent conversions.
How accurate is the atmosphere definition?
The atmosphere is defined as exactly 101325 pascals, making it a precisely defined unit. This definition was established to closely match the average atmospheric pressure at sea level, which can vary slightly depending on weather conditions and geographic location. The exact definition ensures reproducibility in scientific and engineering applications.
What's the difference between atmosphere and bar?
Both atmosphere and bar are units of pressure, but they have slightly different values. One atmosphere equals 101325 pascals, while one bar equals exactly 100000 pascals. This means 1 atm is approximately 1.01325 bar. The bar is more commonly used in meteorology, while atmosphere is more common in chemistry and physics.
How do I convert atmosphere to other units?
Use our atmosphere conversion calculators above, or multiply by the appropriate conversion factor. For example, to convert atmosphere to pascals, multiply by 101325; to convert atmosphere to torr, multiply by 760. For detailed instructions on converting atmosphere to pascals, visit our atm to Pa converter.
What are common uses for atmosphere conversion?
Atmosphere conversion is essential in meteorology (weather reporting), chemistry (gas law calculations), engineering (pressure vessel design), aviation (altitude calculations), and scuba diving (breathing gas calculations). Whether calculating pressure changes in a piston engine or determining safe diving depths, our atmosphere converter tool simplifies these everyday tasks.
How does atmosphere conversion differ from other pressure units?
The atmosphere represents a specific reference pressure (101325 Pa) that approximates Earth's average sea level pressure. This makes it particularly useful for applications involving gases and pressures near this value. Other pressure units like pascals (SI unit) or pounds per square inch (imperial) are more general and can represent any pressure value.
Can I convert very small or very large pressures in atmospheres?
Yes, our atmosphere converter handles both extremely small and large pressures with precision. For vacuum applications, convert pascals to atmospheres (1 Pa = 9.86923e-6 atm). For high-pressure applications, convert atmospheres to bars or pascals. Our smart rounding feature ensures readable results for all scales.
Is your atmosphere conversion tool free to use?
Yes, our atmosphere conversion calculator is completely free with no registration required. Simply enter your value, select your target unit, and get instant, accurate results. We believe precise measurement conversion should be accessible to everyone, from students learning about gas laws to professionals working on complex engineering projects.