Convert bar to atmospheres (atm) for meteorological pressure. Easy-to-use bidirectional pressure unit converter with instant results and step-by-step calculation.
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1 bar = 0.9869 atm
Bar to atmosphere conversion
📊 Conversion in All Pressure Units
📝 Step-by-Step Calculation
📊 Bar to Atmosphere Conversion Chart
Quick reference table for common bar values converted to atmospheres and other pressure units.
Bar
Atmospheres (atm)
PSI (psi)
kPa
0.1 bar
0.0987 atm
1.4504 psi
10.0000 kPa
0.5 bar
0.4935 atm
7.2519 psi
50.0000 kPa
1 bar
0.9869 atm
14.5038 psi
100.0000 kPa
2 bar
1.9738 atm
29.0075 psi
200.0000 kPa
2.5 bar
2.4673 atm
36.2594 psi
250.0000 kPa
3 bar
2.9608 atm
43.5113 psi
300.0000 kPa
5 bar
4.9346 atm
72.5189 psi
500.0000 kPa
10 bar
9.8692 atm
145.0377 psi
1,000.0000 kPa
20 bar
19.7385 atm
290.0755 psi
2,000.0000 kPa
50 bar
49.3462 atm
725.1887 psi
5,000.0000 kPa
100 bar
98.6923 atm
1,450.3774 psi
10,000.0000 kPa
1 bar = 0.986923 atm
The standard conversion factor for bar to atmosphere
📖 How to Use the Bar to Atmosphere Converter
1
Enter the value — Type the number of bar you want to convert in the bar input field, or type an atmosphere value to convert the other way.
2
Instant conversion — The tool automatically converts as you type, showing the result in atmospheres (or bar depending on which field you fill).
3
Review the steps — Below the results, you'll find a step-by-step breakdown of how the conversion was calculated.
4
Use the chart tab — Switch to the Conversion Chart tab for a quick reference table of common bar values.
atm = bar × 0.986923
Multiply the number of bar by 0.986923 to get atmospheres
bar = atm ÷ 0.986923
Divide the atmosphere value by 0.986923 to convert back to bar
Common Pressure Unit Conversion Factors
From
To
Multiply by
bar
atm
0.986923
atm
bar
1.01325
bar
PSI
14.5038
bar
kPa
100
bar
Pa
100,000
bar
torr
750.062
💨
Bidirectional Conversion
Convert seamlessly between bar and atmospheres in both directions. Enter a value in either field and get instant results.
🎯
High Precision
Accurate conversions using the standard factor of 1 bar = 0.986923 atm, with results displayed to 4 decimal places.
📋
Common Values Table
Quick reference chart for frequently used bar values (0.1 to 100 bar) converted to atm, PSI, and kPa.
📖
Step-by-Step Guide
Detailed calculation breakdown showing each step of the conversion process with the formula and intermediate values.
The bar is a metric unit of pressure widely used in meteorology, engineering, and everyday applications such as tire pressure measurement. One bar is defined as exactly 100,000 pascals (Pa), which is roughly equal to the average atmospheric pressure at sea level on Earth (which is about 1.01325 bar or 1 atmosphere). The name "bar" comes from the Greek word "baros," meaning weight.
The bar is commonly used in Europe and many other parts of the world for measuring tire pressure, hydraulic systems, industrial processes, and atmospheric pressure readings. While not an official SI unit, it is accepted for use with the SI system and remains one of the most practical pressure units for real-world applications. Understanding how to convert bar to atmospheres is essential for meteorology, scuba diving, and scientific research.
What Is an Atmosphere?
Atmosphere (atm) is a unit of pressure defined as the average atmospheric pressure at sea level on Earth. One standard atmosphere equals 101,325 pascals (Pa) or 1.01325 bar. The atmosphere is commonly used in meteorology, chemistry, physics, and scuba diving as a reference pressure unit. The relationship between bar and atmosphere is close but not exact — 1 bar is about 1.3% less than 1 atmosphere.
Converting between bar and atmospheres is essential for anyone working with pressure measurements in scientific contexts, weather data interpretation, or equipment that references standard atmospheric pressure.
Why Convert Between Bar and Atmospheres?
Converting between bar and atmospheres is important for a variety of practical and scientific applications:
Meteorology: Weather reports and atmospheric pressure readings are often given in millibars (mbar) or atmospheres. Understanding both units helps interpret weather maps and barometric pressure data.
Scuba Diving: Dive pressure gauges commonly display pressure in bar, while decompression tables and dive computers reference pressure in atmospheres. Accurate conversion is critical for dive safety.
Chemistry and Physics: Many scientific experiments and equations reference the standard atmosphere as a baseline pressure. Converting from bar allows scientists to work with the correct reference values.
Industrial Standards: Equipment specifications from different countries may use bar or atmospheres. Accurate conversion ensures proper system operation and safety across international standards.
Environmental Science: Atmospheric pressure data from different sources may be reported in bar, millibars, or atmospheres. Researchers need to convert between these units for consistent analysis.
Understanding Pressure Scales
Here's a quick comparison to help you visualize pressure values:
1 bar — Approximately 0.987 atmospheres, close to sea-level atmospheric pressure.
1 atm — Standard sea-level atmospheric pressure, equal to 1.01325 bar.
2 bar — Pressure at about 10 meters depth underwater (≈ 1.97 atm).
10 bar — Pressure at about 100 meters depth underwater (≈ 9.87 atm).
200 bar — Typical scuba tank pressure (≈ 197 atm).
Whether you're interpreting weather data, planning a dive, or working on a scientific research project, this converter provides accurate, instant results across all common pressure units.
Frequently Asked Questions
How many atmospheres are in 1 bar?
One bar is equal to 0.986923 atmospheres (atm). This means a pressure of 1 bar is very slightly less than 1 standard atmosphere. To convert bar to atmospheres, multiply the bar value by 0.986923. For example: 2 bar × 0.986923 = 1.9738 atm.
How do I convert bar to atmospheres manually?
To convert bar to atmospheres manually, multiply the number of bar by 0.986923. For example: 2.5 bar × 0.986923 = 2.4673 atm. To convert atmospheres back to bar, divide the atmosphere value by 0.986923, or equivalently, multiply by 1.01325. For quick approximations, you can use the rough estimate that 1 bar ≈ 0.987 atm.
What is the difference between bar and atmosphere?
The bar and the atmosphere (atm) are both units of pressure, but they are defined differently. One bar equals exactly 100,000 pascals, while one standard atmosphere equals exactly 101,325 pascals. This means 1 atm = 1.01325 bar, and 1 bar = 0.986923 atm. The difference is approximately 1.3%. The atmosphere is based on the average sea-level atmospheric pressure on Earth, while the bar is a metric-defined unit. In many practical applications, they are used nearly interchangeably, but the precise difference matters in scientific and engineering contexts.
Why is the atmosphere unit used in meteorology and diving?
The atmosphere (atm) is used in meteorology because it directly represents the average pressure of Earth's atmosphere at sea level, making it intuitive for weather reporting and barometric pressure readings. In scuba diving, the atmosphere is essential because pressure increases by approximately 1 atm for every 10 meters of depth in water. This linear relationship makes it easy for divers to calculate their depth pressure (e.g., at 20 meters, the pressure is about 3 atm — 1 atm from the surface plus 2 atm from the water column). Understanding this relationship is critical for dive planning and decompression safety.
What is the relationship between bar, atm, and PSI?
These three pressure units are commonly used around the world. Key relationships: 1 bar = 0.986923 atm = 14.5038 PSI. 1 atm = 1.01325 bar = 14.6959 PSI. 1 PSI = 0.0689476 bar = 0.0680459 atm. Bar is most common in Europe for tire pressure and industrial use. Atm is used in science, meteorology, and diving. PSI is the standard in the United States for tire pressure and many industrial applications. Our converter handles all these units so you can switch between them instantly.
⚠️ Disclaimer: This Bar to Atmosphere Converter is provided for informational and educational purposes only. While we strive for accuracy using standardized conversion factors, results may be subject to minor rounding differences depending on the level of precision selected. This tool should not be used as the sole basis for critical scientific decisions, safety equipment calibration, or regulatory compliance. Always verify important pressure measurements with calibrated instruments and authoritative sources.