Bar to Standard atmosphere Converter
Enter the value that you want to convert bar to Standard atmosphere (atm) or Standard atmosphere to bar.
1 bar = 0.9869233 Standard atmosphere
Formula: Standard atmosphere = bar value × 0.9869233
bar to Standard atmosphere
10 bar = 9.86923 Standard atmosphere
Popular Pressure Converters:
Bar to Atmosphere in Diving & Industrial Use
Scuba divers use atmospheres to calculate air consumption and decompression stops — every 10 meters of seawater depth adds approximately 1 atm. Industrial pressure gauges often read in bar. Since 1 atm ≈ 1.01325 bar, the values are close but not identical, and the difference matters in precise scientific work, autoclave sterilization settings, and high-pressure chemical reactor specifications.
How Bar Relates to Standard atmosphere
The Bar in Engineering
Bar (bar) is a unit of pressure measurement. 1 bar is equal to 0.9869233 Standard atmosphere.
About the Standard atmosphere
Standard atmosphere (atm) is a unit of pressure measurement. 1 Standard atmosphere is equal to 1.0132500 bar.
Pressure Units Across Industries
Pressure measurements vary dramatically by industry. Meteorologists report in millibars or hectopascals, tire shops use PSI, scuba divers think in atmospheres or bar, vacuum engineers work in torr, and hydraulic systems specify in megapascals. A single industrial plant might encounter all these units across different equipment manuals, safety datasheets, and regulatory standards from different countries.
bar to Standard atmosphere metric conversion table
| 0.01 bar | = | 0.00987 atm |
| 0.1 bar | = | 0.09869 atm |
| 1 bar | = | 0.98692 atm |
| 2 bar | = | 1.97385 atm |
| 3 bar | = | 2.96077 atm |
| 4 bar | = | 3.94769 atm |
| 5 bar | = | 4.93462 atm |
| 6 bar | = | 5.92154 atm |
| 7 bar | = | 6.90846 atm |
| 8 bar | = | 7.89539 atm |
| 9 bar | = | 8.88231 atm |
| 10 bar | = | 9.86923 atm |
| 11 bar | = | 10.85616 atm |
| 12 bar | = | 11.84308 atm |
| 13 bar | = | 12.83000 atm |
| 14 bar | = | 13.81693 atm |
| 15 bar | = | 14.80385 atm |
| 16 bar | = | 15.79077 atm |
| 17 bar | = | 16.77770 atm |
| 18 bar | = | 17.76462 atm |
| 19 bar | = | 18.75154 atm |
| 20 bar | = | 19.73847 atm |
| 30 bar | = | 29.60770 atm |
| 40 bar | = | 39.47693 atm |
| 50 bar | = | 49.34616 atm |
| 60 bar | = | 59.21540 atm |
| 70 bar | = | 69.08463 atm |
| 80 bar | = | 78.95386 atm |
| 90 bar | = | 88.82309 atm |
| 100 bar | = | 98.69233 atm |
| 200 bar | = | 197.38465 atm |
| 300 bar | = | 296.07698 atm |
| 400 bar | = | 394.76931 atm |
| 500 bar | = | 493.46163 atm |
| 600 bar | = | 592.15396 atm |
| 700 bar | = | 690.84629 atm |
| 800 bar | = | 789.53861 atm |
| 900 bar | = | 888.23094 atm |
| 1000 bar | = | 986.92327 atm |
How to Convert Bar to Standard atmosphere?
We can convert bar to Standard atmosphere by using an example.
Example:
Convert 20 Bar to Standard atmosphere?
We know 1 Bar = 0.9869233 Standard atmosphere; 1 Standard atmosphere = 1.0132500 bar.
20 bar = ___atm
20 × 0.9869233 = 19.73847 atm (we know 1 bar = 0.9869233 Standard atmosphere)
Answer:
20 bar = 19.73847 Standard atmosphere
How to Convert Bar to Atmospheres (Step-by-Step)
Converting bar to standard atmospheres (atm) is essential in SCUBA diving, chemistry, and autoclave operation. The conversion factor is 1 bar = 0.986923 atm — the two units are nearly identical in magnitude.
- Write down the pressure value in bar.
- Multiply the bar value by 0.986923.
- The result is the equivalent pressure in atmospheres (atm).
- For a quick approximation, note that 1 bar ≈ 1 atm (only 1.3% difference).
Common Bar to Atmosphere Conversions
Pressures from diving, chemistry, and sterilization applications in both bar and atm.
| Bar | Standard atmosphere |
|---|---|
| 1.0 bar | 0.987 atm |
| 1.01325 bar | 1.000 atm |
| 2.0 bar | 1.974 atm |
| 3.0 bar | 2.961 atm |
| 4.0 bar | 3.948 atm |
| 5.0 bar | 4.935 atm |
| 2.2 bar | 2.171 atm |
| 200 bar | 197.4 atm |
Solved Examples: Bar to Atmospheres
Question 1: A diver is at 30 meters depth where absolute pressure is 4.0 bar. Express this in atmospheres.
Solution:
Pressure in atm = 4.0 × 0.986923
= 3.948 atm
Answer: 4.0 bar = 3.95 atm. This means gases in the diver's lungs are compressed to ~1/4 their surface volume.
Question 2: An autoclave sterilizes at 2.1 bar absolute. How many atmospheres is this?
Solution:
Pressure in atm = 2.1 × 0.986923
= 2.073 atm
Answer: 2.1 bar = 2.07 atm — the standard 121°C sterilization pressure used in hospitals.
Question 3: A chemistry experiment requires 5 atm pressure. A gauge reads in bar. What bar value is needed?
Solution:
We need the inverse: bar = atm ÷ 0.986923
= 5 ÷ 0.986923
= 5.066 bar
Answer: Set the regulator to 5.07 bar to achieve 5 atm for the reaction.
Question 4: A SCUBA tank at 200 bar — how many atmospheres of pressure does this represent?
Solution:
Pressure in atm = 200 × 0.986923
= 197.38 atm
Answer: 200 bar ≈ 197 atm — nearly 200 times atmospheric pressure.
Practice Questions: Bar to Atm
Try solving these on your own to test your understanding:
- Convert 1.5 bar to atm. (Answer: 1.480 atm)
- A pressure vessel operates at 10 bar. Express in atm. (Answer: 9.87 atm)
- Convert 0.5 bar to atm. (Answer: 0.493 atm)
- An oxygen concentrator delivers at 1.4 bar. What is this in atm? (Answer: 1.38 atm)
- Convert 50 bar (Nitrox fill) to atm. (Answer: 49.35 atm)
SCUBA Diving: Bar and Atmospheres Underwater
Divers experience 1 additional atmosphere of pressure for every 10 meters of seawater depth. At 30 m, total absolute pressure is ~4 atm (~4.05 bar). This affects gas consumption (air volume consumed is proportional to absolute pressure), decompression obligations, and nitrogen narcosis onset (~4 atm / 30 m). Dive computers display depth, but understanding the bar-to-atm relationship helps calculate breathing gas requirements manually.
Autoclaves and Sterilization Pressures
Medical and laboratory autoclaves use pressurized steam for sterilization. Standard cycles run at 1.1 bar gauge pressure (2.1 bar absolute ≈ 2.07 atm) at 121°C for 15-30 minutes. Higher cycles at 1.4 bar gauge (2.4 bar ≈ 2.37 atm) reach 134°C for prion decontamination. These pressures are needed because water's boiling point increases with pressure, enabling temperatures above 100°C for killing microorganisms.
Chemistry and Ideal Gas Law
The ideal gas law (PV = nRT) historically uses atmospheres when R = 0.0821 L·atm/(mol·K). Modern practice often uses bar with R = 0.08314 L·bar/(mol·K). Since 1 bar ≈ 0.987 atm, results are nearly identical. Chemical equilibrium constants (Kp) may be quoted in either unit — always check which convention a textbook uses. Reactions at "elevated pressure" in chemistry typically mean 5-200 atm.
Key Takeaways
- 1 bar = 0.986923 atm — the two units differ by only 1.3%.
- For diving: 1 bar ≈ 1 atm is accurate enough for practical calculations.
- Depth pressure: add 1 atm (~1 bar) per 10 meters of seawater.
- Autoclave sterilization: 2.1 bar absolute ≈ 2 atm at 121°C.
- Standard atmosphere = 1.01325 bar exactly (by definition).
- In chemistry, check whether equations use atm or bar for the gas constant R.
Bar to Standard atmosphere Conversion Formula
Standard atmosphere = bar × 0.9869233
1 bar = 0.9869233 Standard atmosphere
1 Standard atmosphere = 1.0132500 bar
Reverse: bar = Standard atmosphere × 1.0132500
Frequently Asked Questions
How many Standard atmosphere are in 1 bar?
There are 0.9869233 Standard atmosphere in 1 bar. To convert bar to Standard atmosphere, multiply the value by 0.9869233.
How do I convert bar to Standard atmosphere?
Multiply your bar value by 0.9869233 to get the equivalent in Standard atmosphere. For example, 5 bar = 5 × 0.9869233 = 4.93462 Standard atmosphere.
How do I convert Standard atmosphere to bar?
Multiply your Standard atmosphere value by 1.0132500 to get the equivalent in bar. Alternatively, divide by 0.9869233.
What is 10 bar in Standard atmosphere?
10 bar is equal to 9.86923 Standard atmosphere.
What is 100 bar in Standard atmosphere?
100 bar is equal to 98.69233 Standard atmosphere.