Convert Bar to Standard atmosphere
1 bar = 0.9869233 standard atmosphere (atm). For example, 10 bar = 9.869233 standard atmosphere and 100 bar = 98.69233 standard atmosphere. Type any value below to convert bar to standard atmosphere both ways — it runs entirely in your browser.
Quick answer: Bar to Standard atmosphere
1 Bar = 0.9869233 Standard atmosphere (bar → atm). To convert bar to standard atmosphere, multiply by 0.9869233. To convert standard atmosphere to bar, multiply by 1.01325. The converter at the top does this instantly and both ways; the sections below give the formula, worked examples, a full conversion chart and answers to the most common bar-to-standard atmosphere questions.
How to convert Bar to Standard atmosphere
To convert bar to standard atmosphere, multiply the number of bar by the conversion factor 0.9869233, because 1 bar = 0.9869233 atm. The conversion is linear, so the same factor works for any value — whole numbers, decimals or fractions. For the reverse direction, 1 atm = 1.01325 bar, so you divide by 0.9869233 (or multiply by 1.01325) to turn standard atmosphere back into bar.
atm = bar × 0.9869233 ·
bar = atm × 1.01325
- Write down the value you want to convert, in bar.
- Multiply it by 0.9869233.
- The result is the same area/length/quantity expressed in standard atmosphere.
Bar to Standard atmosphere — worked examples
Each row shows the exact arithmetic so you can follow the conversion step by step. For example, 5 bar is 4.934616 standard atmosphere because 5 bar × 0.9869233 = 4.934616 atm.
| Bar | Calculation | Standard atmosphere |
|---|---|---|
| 1 bar | 1 bar × 0.9869233 = 0.9869233 atm | 0.9869233 atm |
| 2 bar | 2 bar × 0.9869233 = 1.973847 atm | 1.973847 atm |
| 3 bar | 3 bar × 0.9869233 = 2.96077 atm | 2.96077 atm |
| 5 bar | 5 bar × 0.9869233 = 4.934616 atm | 4.934616 atm |
| 7 bar | 7 bar × 0.9869233 = 6.908463 atm | 6.908463 atm |
| 10 bar | 10 bar × 0.9869233 = 9.869233 atm | 9.869233 atm |
| 12 bar | 12 bar × 0.9869233 = 11.84308 atm | 11.84308 atm |
| 15 bar | 15 bar × 0.9869233 = 14.80385 atm | 14.80385 atm |
| 20 bar | 20 bar × 0.9869233 = 19.73847 atm | 19.73847 atm |
| 25 bar | 25 bar × 0.9869233 = 24.67308 atm | 24.67308 atm |
| 50 bar | 50 bar × 0.9869233 = 49.34616 atm | 49.34616 atm |
| 100 bar | 100 bar × 0.9869233 = 98.69233 atm | 98.69233 atm |
Common Bar to Standard atmosphere conversions
These are the bar-to-standard atmosphere values people look up most often. Every figure is computed from the exact factor, so you can rely on them for quick reference:
- 1 bar = 0.9869233 standard atmosphere
- 2 bar = 1.973847 standard atmosphere
- 2.5 bar = 2.467308 standard atmosphere
- 3 bar = 2.96077 standard atmosphere
- 4 bar = 3.947693 standard atmosphere
- 5 bar = 4.934616 standard atmosphere
- 6 bar = 5.92154 standard atmosphere
- 7 bar = 6.908463 standard atmosphere
- 8 bar = 7.895386 standard atmosphere
- 9 bar = 8.882309 standard atmosphere
- 10 bar = 9.869233 standard atmosphere
- 12 bar = 11.84308 standard atmosphere
- 15 bar = 14.80385 standard atmosphere
- 20 bar = 19.73847 standard atmosphere
- 25 bar = 24.67308 standard atmosphere
- 30 bar = 29.6077 standard atmosphere
- 50 bar = 49.34616 standard atmosphere
- 75 bar = 74.01925 standard atmosphere
- 100 bar = 98.69233 standard atmosphere
- 200 bar = 197.3847 standard atmosphere
- 500 bar = 493.4616 standard atmosphere
- 1000 bar = 986.9233 standard atmosphere
Bar to Standard atmosphere conversion chart (both directions)
The chart below converts bar to standard atmosphere and standard atmosphere to bar side by side, so it works whichever way you need. 1 bar = 0.9869233 standard atmosphere, and 1 standard atmosphere = 1.01325 bar.
| Bar → Standard atmosphere | Standard atmosphere → Bar |
|---|---|
| 0.25 bar = 0.2467308 atm | 0.25 atm = 0.2533125 bar |
| 0.5 bar = 0.4934616 atm | 0.5 atm = 0.506625 bar |
| 1 bar = 0.9869233 atm | 1 atm = 1.01325 bar |
| 2 bar = 1.973847 atm | 2 atm = 2.0265 bar |
| 3 bar = 2.96077 atm | 3 atm = 3.03975 bar |
| 4 bar = 3.947693 atm | 4 atm = 4.053 bar |
| 5 bar = 4.934616 atm | 5 atm = 5.06625 bar |
| 6 bar = 5.92154 atm | 6 atm = 6.0795 bar |
| 7 bar = 6.908463 atm | 7 atm = 7.09275 bar |
| 8 bar = 7.895386 atm | 8 atm = 8.106 bar |
| 9 bar = 8.882309 atm | 9 atm = 9.11925 bar |
| 10 bar = 9.869233 atm | 10 atm = 10.1325 bar |
| 12 bar = 11.84308 atm | 12 atm = 12.159 bar |
| 15 bar = 14.80385 atm | 15 atm = 15.19875 bar |
| 20 bar = 19.73847 atm | 20 atm = 20.265 bar |
| 25 bar = 24.67308 atm | 25 atm = 25.33125 bar |
| 30 bar = 29.6077 atm | 30 atm = 30.3975 bar |
| 40 bar = 39.47693 atm | 40 atm = 40.53 bar |
| 50 bar = 49.34616 atm | 50 atm = 50.6625 bar |
| 75 bar = 74.01925 atm | 75 atm = 75.99375 bar |
| 100 bar = 98.69233 atm | 100 atm = 101.325 bar |
| 150 bar = 148.0385 atm | 150 atm = 151.9875 bar |
| 200 bar = 197.3847 atm | 200 atm = 202.65 bar |
| 250 bar = 246.7308 atm | 250 atm = 253.3125 bar |
| 500 bar = 493.4616 atm | 500 atm = 506.625 bar |
| 1000 bar = 986.9233 atm | 1000 atm = 1,013.25 bar |
Bar vs Standard atmosphere: which is bigger?
A standard atmosphere is the larger unit: one standard atmosphere equals 1.01325 bars. Put another way, you need 1.01325 bars to make a single standard atmosphere.
What is a Bar? History, origin and usage
The bar takes its name from the Greek báros, meaning weight. It was deliberately defined as exactly 100,000 pascals, a round number chosen to sit very close to average air pressure at sea level, so that a pressure "in bars" reads roughly as "how many atmospheres". It is not an SI unit, but the International Bureau of Weights and Measures lists it among the units accepted for use alongside SI.
Bars are the everyday pressure unit across most of Europe and much of Asia: tyre inflators, bicycle pumps, espresso machines, diving cylinders, pressure washers and boiler gauges. An espresso machine is conventionally built around 9 bar of brewing pressure.
A bar is close to, but not the same as, an atmosphere — one atmosphere is 1.01325 bar exactly, a difference of about 1.3%. Diving uses this closeness deliberately: seawater adds roughly one bar of pressure for every ten metres of depth.
What is a Standard atmosphere? History, origin and usage
The standard atmosphere was fixed by the 10th General Conference on Weights and Measures in 1954 at exactly 101,325 pascals. Before that, "one atmosphere" meant whatever a 760 mm mercury column happened to weigh, which depended on local gravity and on the temperature of the mercury — so the same experiment gave slightly different answers in different laboratories. Fixing it as a defined number ended that.
Atmospheres are used in chemistry, physics, diving and any field that talks about pressure as a multiple of ordinary air pressure — reaction conditions, gas laws, hyperbaric medicine and pressure-vessel ratings.
It is a defined constant, not a measurement, so it never changes with the weather or with where you are standing. Real sea-level pressure wanders a few per cent either side of it every week. The deepest point of the ocean sits at roughly 1,100 atmospheres.
Convert 1 Bar to other units
It can help to see a bar next to the other units it is commonly compared with. One bar (bar) is equal to:
| 1 Bar equals | Unit |
|---|---|
| 100,000 Pa | Pascal |
| 1,000 hPa | Hectopascal |
| 100 kPa | Kilopascal |
| 0.1 MPa | Megapascal |
| 1,000 mbar | Millibar |
| 0.9869233 atm | Standard atmosphere |
| 750.0617 Torr | Torr |
| 750.0616 mmHg | Millimetre of mercury |
| 29.52998 inHg | Inch of mercury |
| 10,197.16 mmH₂O | Millimetre of water |
| 401.4631 inH₂O | Inch of water |
| 14.50377 psi | Pound per square inch |
| 1.019716 kgf/cm² | Kilogram-force per square centimetre |
Convert 1 Standard atmosphere to other units
One standard atmosphere (atm) is equal to:
| 1 Standard atmosphere equals | Unit |
|---|---|
| 101,325 Pa | Pascal |
| 1,013.25 hPa | Hectopascal |
| 101.325 kPa | Kilopascal |
| 0.101325 MPa | Megapascal |
| 1,013.25 mbar | Millibar |
| 1.01325 bar | Bar |
| 760 Torr | Torr |
| 759.9999 mmHg | Millimetre of mercury |
| 29.92126 inHg | Inch of mercury |
| 10,332.27 mmH₂O | Millimetre of water |
| 406.7825 inH₂O | Inch of water |
| 14.69595 psi | Pound per square inch |
| 1.033227 kgf/cm² | Kilogram-force per square centimetre |
Tips for converting Bar to Standard atmosphere
- To go from bar to standard atmosphere, multiply by 0.9869233; to go back, divide by 0.9869233 (or multiply by 1.01325).
- For a quick mental estimate, remember that 1 bar ≈ 0.9869233 standard atmosphere, so 10 bar ≈ 9.869233 standard atmosphere.
- The converter above keeps full precision; the tables round for readability, so use the tool for exact figures.
- Both fields update live as you type — change either side to convert in that direction.
How to use this Bar to Standard atmosphere converter
Type a number into the Bar field and the equivalent in Standard atmosphere appears instantly — there is no “convert” button to press and nothing is sent to a server, so it works offline once the page has loaded and is safe for any data. You can also type into the Standard atmosphere field to convert the other way (standard atmosphere to bar). Use the swap control to flip the two units, and copy the result with a single click. Because the calculation runs in your browser with full floating-point precision, the converter is more exact than the rounded figures shown in the reference chart above — use the chart for quick look-ups and the tool for precise work.
Accuracy and method
Every figure on this page — the formula, the worked examples, the conversion chart and the “convert to other units” tables — is computed from a single verified conversion factor (1 bar = 0.9869233 atm), never copied from a hand-typed lookup table that could drift. That factor is derived from each unit’s definition in terms of a common base unit, and an automated check re-verifies all of the site’s factors on every update, so the numbers here stay correct over time. This matters for bar-to-standard atmosphere conversions because a small rounding error in a published table compounds quickly at larger quantities; computing from the exact factor avoids that.
Sources
- BIPM — The International System of Units (SI Brochure) — the defining document for the SI, published by the International Bureau of Weights and Measures. It fixes the base unit that this conversion resolves to, which is why the factor here can be exact rather than approximate.
- NIST — Definitions of the SI base units — the US National Institute of Standards and Technology reference for the SI base units, used here as an independent cross-check on the base-unit definition.
Pressure factors here come from fixed definitions, anchored to the pascal: a bar is exactly 100,000 Pa, one atmosphere is exactly 101,325 Pa, a torr is exactly a 760th of an atmosphere, and psi is built from the exact pound and the exact inch. Two of them — psi and the torr — work out to decimals that repeat forever, so where a number is shown rounded it is marked, not quietly trimmed.
Frequently asked questions
- How many standard atmosphere are in 1 bar?
- 1 bar = 0.9869233 standard atmosphere (atm). To convert any number of bar to standard atmosphere, multiply by 0.9869233.
- How do I convert bar to standard atmosphere?
- Multiply the number of bar by 0.9869233. For example, 10 bar = 10 × 0.9869233 = 9.869233 standard atmosphere, and 25 bar = 24.67308 standard atmosphere.
- How many bar are in 1 standard atmosphere?
- 1 standard atmosphere = 1.01325 bar. So to convert standard atmosphere back to bar, multiply by 1.01325.
- What is the formula to convert bar to standard atmosphere?
- standard atmosphere = bar × 0.9869233. The reverse formula is bar = standard atmosphere × 1.01325.
- How much is 100 bar in standard atmosphere?
- 100 bar = 98.69233 standard atmosphere. (And 1000 bar = 986.9233 standard atmosphere.)
- Which is bigger, a bar or a standard atmosphere?
- A standard atmosphere is larger: 1 standard atmosphere = 1.01325 bar.
- Is this bar to standard atmosphere converter accurate?
- Yes — every value is computed from the exact 0.9869233 atm per bar factor (not rounded look-up tables), and the factors are re-verified automatically on every update.
- Can I convert standard atmosphere to bar too?
- Yes. The converter works both ways — enter a value in either field. 1 standard atmosphere = 1.01325 bar.