Convert Standard atmosphere to Bar
1 standard atmosphere = 1.01325 bar (bar). For example, 10 standard atmosphere = 10.1325 bar and 100 standard atmosphere = 101.325 bar. Type any value below to convert standard atmosphere to bar both ways — it runs entirely in your browser.
Quick answer: Standard atmosphere to Bar
1 Standard atmosphere = 1.01325 Bar (atm → bar). To convert standard atmosphere to bar, multiply by 1.01325. To convert bar to standard atmosphere, multiply by 0.9869233. 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 standard atmosphere-to-bar questions.
How to convert Standard atmosphere to Bar
To convert standard atmosphere to bar, multiply the number of standard atmosphere by the conversion factor 1.01325, because 1 atm = 1.01325 bar. The conversion is linear, so the same factor works for any value — whole numbers, decimals or fractions. For the reverse direction, 1 bar = 0.9869233 atm, so you divide by 1.01325 (or multiply by 0.9869233) to turn bar back into standard atmosphere.
bar = atm × 1.01325 ·
atm = bar × 0.9869233
- Write down the value you want to convert, in standard atmosphere.
- Multiply it by 1.01325.
- The result is the same area/length/quantity expressed in bar.
Standard atmosphere to Bar — worked examples
Each row shows the exact arithmetic so you can follow the conversion step by step. For example, 5 standard atmosphere is 5.06625 bar because 5 atm × 1.01325 = 5.06625 bar.
| Standard atmosphere | Calculation | Bar |
|---|---|---|
| 1 atm | 1 atm × 1.01325 = 1.01325 bar | 1.01325 bar |
| 2 atm | 2 atm × 1.01325 = 2.0265 bar | 2.0265 bar |
| 3 atm | 3 atm × 1.01325 = 3.03975 bar | 3.03975 bar |
| 5 atm | 5 atm × 1.01325 = 5.06625 bar | 5.06625 bar |
| 7 atm | 7 atm × 1.01325 = 7.09275 bar | 7.09275 bar |
| 10 atm | 10 atm × 1.01325 = 10.1325 bar | 10.1325 bar |
| 12 atm | 12 atm × 1.01325 = 12.159 bar | 12.159 bar |
| 15 atm | 15 atm × 1.01325 = 15.19875 bar | 15.19875 bar |
| 20 atm | 20 atm × 1.01325 = 20.265 bar | 20.265 bar |
| 25 atm | 25 atm × 1.01325 = 25.33125 bar | 25.33125 bar |
| 50 atm | 50 atm × 1.01325 = 50.6625 bar | 50.6625 bar |
| 100 atm | 100 atm × 1.01325 = 101.325 bar | 101.325 bar |
Common Standard atmosphere to Bar conversions
These are the standard atmosphere-to-bar values people look up most often. Every figure is computed from the exact factor, so you can rely on them for quick reference:
- 1 standard atmosphere = 1.01325 bar
- 2 standard atmosphere = 2.0265 bar
- 2.5 standard atmosphere = 2.533125 bar
- 3 standard atmosphere = 3.03975 bar
- 4 standard atmosphere = 4.053 bar
- 5 standard atmosphere = 5.06625 bar
- 6 standard atmosphere = 6.0795 bar
- 7 standard atmosphere = 7.09275 bar
- 8 standard atmosphere = 8.106 bar
- 9 standard atmosphere = 9.11925 bar
- 10 standard atmosphere = 10.1325 bar
- 12 standard atmosphere = 12.159 bar
- 15 standard atmosphere = 15.19875 bar
- 20 standard atmosphere = 20.265 bar
- 25 standard atmosphere = 25.33125 bar
- 30 standard atmosphere = 30.3975 bar
- 50 standard atmosphere = 50.6625 bar
- 75 standard atmosphere = 75.99375 bar
- 100 standard atmosphere = 101.325 bar
- 200 standard atmosphere = 202.65 bar
- 500 standard atmosphere = 506.625 bar
- 1000 standard atmosphere = 1,013.25 bar
Standard atmosphere to Bar conversion chart (both directions)
The chart below converts standard atmosphere to bar and bar to standard atmosphere side by side, so it works whichever way you need. 1 standard atmosphere = 1.01325 bar, and 1 bar = 0.9869233 standard atmosphere.
| Standard atmosphere → Bar | Bar → Standard atmosphere |
|---|---|
| 0.25 atm = 0.2533125 bar | 0.25 bar = 0.2467308 atm |
| 0.5 atm = 0.506625 bar | 0.5 bar = 0.4934616 atm |
| 1 atm = 1.01325 bar | 1 bar = 0.9869233 atm |
| 2 atm = 2.0265 bar | 2 bar = 1.973847 atm |
| 3 atm = 3.03975 bar | 3 bar = 2.96077 atm |
| 4 atm = 4.053 bar | 4 bar = 3.947693 atm |
| 5 atm = 5.06625 bar | 5 bar = 4.934616 atm |
| 6 atm = 6.0795 bar | 6 bar = 5.92154 atm |
| 7 atm = 7.09275 bar | 7 bar = 6.908463 atm |
| 8 atm = 8.106 bar | 8 bar = 7.895386 atm |
| 9 atm = 9.11925 bar | 9 bar = 8.882309 atm |
| 10 atm = 10.1325 bar | 10 bar = 9.869233 atm |
| 12 atm = 12.159 bar | 12 bar = 11.84308 atm |
| 15 atm = 15.19875 bar | 15 bar = 14.80385 atm |
| 20 atm = 20.265 bar | 20 bar = 19.73847 atm |
| 25 atm = 25.33125 bar | 25 bar = 24.67308 atm |
| 30 atm = 30.3975 bar | 30 bar = 29.6077 atm |
| 40 atm = 40.53 bar | 40 bar = 39.47693 atm |
| 50 atm = 50.6625 bar | 50 bar = 49.34616 atm |
| 75 atm = 75.99375 bar | 75 bar = 74.01925 atm |
| 100 atm = 101.325 bar | 100 bar = 98.69233 atm |
| 150 atm = 151.9875 bar | 150 bar = 148.0385 atm |
| 200 atm = 202.65 bar | 200 bar = 197.3847 atm |
| 250 atm = 253.3125 bar | 250 bar = 246.7308 atm |
| 500 atm = 506.625 bar | 500 bar = 493.4616 atm |
| 1000 atm = 1,013.25 bar | 1000 bar = 986.9233 atm |
Standard atmosphere vs Bar: 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 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.
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.
Convert 1 Standard atmosphere to other units
It can help to see a standard atmosphere next to the other units it is commonly compared with. 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 |
Convert 1 Bar to other units
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 |
Tips for converting Standard atmosphere to Bar
- To go from standard atmosphere to bar, multiply by 1.01325; to go back, divide by 1.01325 (or multiply by 0.9869233).
- For a quick mental estimate, remember that 1 standard atmosphere ≈ 1.01325 bar, so 10 standard atmosphere ≈ 10.1325 bar.
- 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 Standard atmosphere to Bar converter
Type a number into the Standard atmosphere field and the equivalent in Bar 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 Bar field to convert the other way (bar to standard atmosphere). 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 atm = 1.01325 bar), 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 standard atmosphere-to-bar 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 bar are in 1 standard atmosphere?
- 1 standard atmosphere = 1.01325 bar (bar). To convert any number of standard atmosphere to bar, multiply by 1.01325.
- How do I convert standard atmosphere to bar?
- Multiply the number of standard atmosphere by 1.01325. For example, 10 standard atmosphere = 10 × 1.01325 = 10.1325 bar, and 25 standard atmosphere = 25.33125 bar.
- How many standard atmosphere are in 1 bar?
- 1 bar = 0.9869233 standard atmosphere. So to convert bar back to standard atmosphere, multiply by 0.9869233.
- What is the formula to convert standard atmosphere to bar?
- bar = standard atmosphere × 1.01325. The reverse formula is standard atmosphere = bar × 0.9869233.
- How much is 100 standard atmosphere in bar?
- 100 standard atmosphere = 101.325 bar. (And 1000 standard atmosphere = 1,013.25 bar.)
- Which is bigger, a standard atmosphere or a bar?
- A standard atmosphere is larger: 1 standard atmosphere = 1.01325 bar.
- Is this standard atmosphere to bar converter accurate?
- Yes — every value is computed from the exact 1.01325 bar per atm factor (not rounded look-up tables), and the factors are re-verified automatically on every update.
- Can I convert bar to standard atmosphere too?
- Yes. The converter works both ways — enter a value in either field. 1 bar = 0.9869233 standard atmosphere.