How many atm is 1 bar?

0.986923266716 atm, which is about 1.3 percent short of a full atmosphere. The bar is fixed at 100,000 pascals and the standard atmosphere at 101,325 pascals, so every bar is 1,325 Pa light. The figures scale straight from there: 2 bar is 1.97384653343 atm, 3 bar is 2.96076980015 atm, 5 bar is 4.93461633358 atm, 10 bar is 9.86923266716 atm and 100 bar is 98.6923266716 atm.

What is the formula for bar to atm?

atm = bar × 100,000 / 101,325, which is exactly 4,000/4,053 and never terminates as a decimal, so the page rounds at twelve significant digits and shows 0.986923266716 for one bar. Going the other way is exact: bar = atm × 1.01325, so 1 atm is 1.01325 bar, 2 atm is 2.0265 bar and 10 atm is 10.1325 bar. The swap button between the two boxes turns the page around, and it keeps the number you typed rather than the answer, so it converts that same figure in the new direction.

Why is a bar not exactly one atmosphere?

The two units have different fixed definitions: 1 bar is exactly 100,000 Pa, while 1 standard atmosphere is exactly 101,325 Pa. The difference is 1,325 Pa, so 1 bar displays as 0.986923266716 atm and 1 atm is exactly 1.01325 bar. A torr is exactly 1/760 of a standard atmosphere; the conventional millimeter of mercury listed here is close to, but distinct from, a torr.

Worked example: what is 200 bar in atmospheres?

197.384653343 atm. Type 200 into the From box and the answer appears as you type. The list gives the same pressure as 20,000,000 Pa, 20,000 kPa and 2,900.7547546 psi, with a Copy button for each row. Copy result copies the plain headline value, 197.384653343, without display separators.

Is this gauge pressure or absolute pressure?

The converter changes units and preserves the pressure reference: 1 bar gauge becomes 0.986923266716 atm gauge, while 1 bar absolute becomes 0.986923266716 atm absolute. Moving from gauge to absolute requires adding the actual ambient pressure. Assuming ambient pressure is exactly one standard atmosphere, 1 bar gauge corresponds to 2.01325 bar absolute. Ambient pressure varies; the converter does not measure or add it.

Can it convert millibar or hectopascal?

Not as their own entries: the pressure menu holds pascal, kilopascal, bar, pound per square inch, atmosphere and millimetre of mercury. A millibar is one thousandth of a bar, and a hectopascal is the same size, so divide the millibar figure by 1,000 and type it in the bar box. A sea-level 1,013.25 mbar is 1.01325 bar, which reads exactly 1 atm, and 1 mbar is 0.001 bar, which reads 0.000986923266716 atm.

What is 1 bar in psi and kPa?

14.503773773 psi and exactly 100 kPa, both printed in the list under the answer without changing a setting, alongside 100,000 Pa. Millimetres of mercury sit behind the Uncommon units switch in the row under the converter, labelled Show 1 more on this category, where 1 bar is 750.061575846 mmHg. Picking any of those units in the To menu promotes it to the headline instead.

How precise are the answers?

Results round to twelve significant digits from the written decimal. The factor 4,000/4,053 is exact, but its decimal expansion repeats, so the displayed answer is rounded. Magnitudes below 0.000001 switch to exponential notation: 0.000001 bar displays as 9.86923266716e-7 atm, while 0.001 bar displays as 0.000986923266716 atm. The psi row uses the converter’s stated rounded psi coefficient.

Does anything I type leave the page?

Your input and converted values are calculated in the browser and are not uploaded by the converter. Its listed factors arrive with the page, including the stated rounded psi coefficient, so conversion needs no external lookup and keeps working offline after the page has loaded.

Bar to atm Converter

A bar is defined as exactly 100,000 pascals and the standard atmosphere is defined as exactly 101,325 pascals, so bar to atm is a multiplication by 100,000/101,325, a fraction that reduces to exactly 4,000/4,053 and prints here as 0.986923266716. One bar is therefore a little under one atmosphere: 1 bar is 0.986923266716 atm, 2 bar is 1.97384653343 atm, 10 bar is 9.86923266716 atm and a 200 bar cylinder is 197.384653343 atm. The reverse direction is the tidy one, because 1 atm is exactly 1.01325 bar, so 1,013.25 bar comes back as exactly 1,000 atm. This page opens the converter with Bar in the From box and Atmosphere in the To box, ahead of whatever pair you last used, and it answers as you type, to twelve significant digits. Under the answer the same pressure is listed in pascals, kilopascals and pounds per square inch at once, so 1 bar reads 100,000 Pa, 100 kPa and 14.503773773 psi, with millimetres of mercury at 750.061575846 once the Show 1 more switch is on. It converts units and nothing else: whether the reading on your gauge is absolute or measured against the air around it is something the number alone cannot say.

From

To0.986923266716

Category: Pressure

Base unit: pascal

Uncommon units: Show 1 more

One standard atmosphere is 101,325 Pa. mmHg is the conventional 133.322387415 Pa, distinct from the torr (exactly 101,325/760 Pa). The psi coefficient is rounded to 6,894.757293168 Pa. Converting units preserves gauge or absolute reference; it does not add ambient pressure.

Results round to 12 significant digits using the listed unit definitions. Input must have a finite numeric magnitude and at most 512 significant digits. Type a single decimal or scientific number; a matching From unit suffix is accepted. Commas and grouped spaces separate thousands; decimal commas, fractions and compound measurements are refused.

1 bar in every pressure unit

PascalPa
100,000
KilopascalkPa
100
Pound per square inchpsi
14.503773773
Atmosphereatm
0.986923266716

Selectable complete conversion

Unit Converter — Pressure
Input: 1 (Bar, bar)
Result: 0.986923266716 atm (Atmosphere)
Displayed values round to 12 significant digits.
One standard atmosphere is 101,325 Pa. mmHg is the conventional 133.322387415 Pa, distinct from the torr (exactly 101,325/760 Pa). The psi coefficient is rounded to 6,894.757293168 Pa. Converting units preserves gauge or absolute reference; it does not add ambient pressure.
All other units:
Pascal (Pa): 100000
Kilopascal (kPa): 100
Pound per square inch (psi): 14.503773773
Atmosphere (atm): 0.986923266716
Millimeter of mercury (mmHg): 750.061575846

Common questions

How many atm is 1 bar?: 0.986923266716 atm, which is about 1.3 percent short of a full atmosphere. The bar is fixed at 100,000 pascals and the standard atmosphere at 101,325 pascals, so every bar is 1,325 Pa light. The figures scale straight from there: 2 bar is 1.97384653343 atm, 3 bar is 2.96076980015 atm, 5 bar is 4.93461633358 atm, 10 bar is 9.86923266716 atm and 100 bar is 98.6923266716 atm.
What is the formula for bar to atm?: atm = bar × 100,000 / 101,325, which is exactly 4,000/4,053 and never terminates as a decimal, so the page rounds at twelve significant digits and shows 0.986923266716 for one bar. Going the other way is exact: bar = atm × 1.01325, so 1 atm is 1.01325 bar, 2 atm is 2.0265 bar and 10 atm is 10.1325 bar. The swap button between the two boxes turns the page around, and it keeps the number you typed rather than the answer, so it converts that same figure in the new direction.
Why is a bar not exactly one atmosphere?: The two units have different fixed definitions: 1 bar is exactly 100,000 Pa, while 1 standard atmosphere is exactly 101,325 Pa. The difference is 1,325 Pa, so 1 bar displays as 0.986923266716 atm and 1 atm is exactly 1.01325 bar. A torr is exactly 1/760 of a standard atmosphere; the conventional millimeter of mercury listed here is close to, but distinct from, a torr.
Worked example: what is 200 bar in atmospheres?: 197.384653343 atm. Type 200 into the From box and the answer appears as you type. The list gives the same pressure as 20,000,000 Pa, 20,000 kPa and 2,900.7547546 psi, with a Copy button for each row. Copy result copies the plain headline value, 197.384653343, without display separators.
Is this gauge pressure or absolute pressure?: The converter changes units and preserves the pressure reference: 1 bar gauge becomes 0.986923266716 atm gauge, while 1 bar absolute becomes 0.986923266716 atm absolute. Moving from gauge to absolute requires adding the actual ambient pressure. Assuming ambient pressure is exactly one standard atmosphere, 1 bar gauge corresponds to 2.01325 bar absolute. Ambient pressure varies; the converter does not measure or add it.
Can it convert millibar or hectopascal?: Not as their own entries: the pressure menu holds pascal, kilopascal, bar, pound per square inch, atmosphere and millimetre of mercury. A millibar is one thousandth of a bar, and a hectopascal is the same size, so divide the millibar figure by 1,000 and type it in the bar box. A sea-level 1,013.25 mbar is 1.01325 bar, which reads exactly 1 atm, and 1 mbar is 0.001 bar, which reads 0.000986923266716 atm.
What is 1 bar in psi and kPa?: 14.503773773 psi and exactly 100 kPa, both printed in the list under the answer without changing a setting, alongside 100,000 Pa. Millimetres of mercury sit behind the Uncommon units switch in the row under the converter, labelled Show 1 more on this category, where 1 bar is 750.061575846 mmHg. Picking any of those units in the To menu promotes it to the headline instead.
How precise are the answers?: Results round to twelve significant digits from the written decimal. The factor 4,000/4,053 is exact, but its decimal expansion repeats, so the displayed answer is rounded. Magnitudes below 0.000001 switch to exponential notation: 0.000001 bar displays as 9.86923266716e-7 atm, while 0.001 bar displays as 0.000986923266716 atm. The psi row uses the converter’s stated rounded psi coefficient.
Does anything I type leave the page?: Your input and converted values are calculated in the browser and are not uploaded by the converter. Its listed factors arrive with the page, including the stated rounded psi coefficient, so conversion needs no external lookup and keeps working offline after the page has loaded.

Results round to 12 significant digits using the listed unit conventions. Many factors are exact definitions; psi and parsec use rounded coefficients. Temperature includes scale offsets. Days and weeks are fixed-duration units, and unit conversion does not determine calendar dates, ambient pressure or a software label’s convention.