Pressure ConverterFree online other calculator — instant results, no sign-up
Convert standard pressure units.
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About the Pressure Converter
The Pressure Converter converts a pressure value between pascal, psi, bar, and atmosphere. It uses fixed unit relationships to express the same pressure in your selected unit. With the default inputs of 1 pascal converted to atmosphere, the displayed result is 0.00001 atmosphere.
- Value
- The pressure magnitude to convert, expressed in the selected From unit; the default is 1.
- From
- The unit of the entered pressure—pascal, psi, bar, or atmosphere—with pascal selected by default.
- To
- The unit for the converted pressure—atmosphere, bar, psi, or pascal—with atmosphere selected by default.
Formula and method
P_to = P_from × (C_from / C_to), where C_pascal = 1, C_psi ≈ 6894.757293168, C_bar = 100000, and C_atmosphere = 101325 pascals per unit. For the default inputs: P_to = 1 × (1 / 101325) atmosphere ≈ 0.000009869232667 atmosphere, displayed as 0.00001 atmosphere.
- P_fromThe entered pressure magnitude in the From unit.
- P_toThe converted pressure magnitude in the To unit before display rounding.
- C_fromThe number of pascals in one unit of the selected From unit.
- C_toThe number of pascals in one unit of the selected To unit.
Multiply the entered value by the source unit's pascal conversion factor, then divide by the target unit's pascal conversion factor. This uses pascals as an intermediate unit without changing the physical pressure. The default conversion divides 1 pascal by 101325 pascals per atmosphere; rounding to five decimal places gives the supplied result of 0.00001 atmosphere.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Value1
- Frompascal
- Toatmosphere
Results
- Result0.00001 atmosphere
How to use the Pressure Converter
- 1Enter the pressure magnitude in Value; leave it at 1 to follow the default example.
- 2Select the pressure's original unit in From; use pascal for the default example.
- 3Select the desired output unit in To; use atmosphere for the default example.
- 4Read the Result in the selected To unit: the default inputs display 0.00001 atmosphere.
- 5Account for display rounding when using the result in further calculations, especially for small pressure values.
Reading your result
The Result row shows the entered pressure expressed in the To unit. For the default inputs, Result = 0.00001 atmosphere is the rounded equivalent of 1 pascal, not an exact equality at the displayed precision. The numerical magnitude changes because the unit changes; the underlying pressure stays the same.
Limitations
This tool converts units only; it does not change a pressure's reference basis between absolute, gauge, or differential pressure. Atmosphere means the standard atmosphere of exactly 101325 pascals, not the local atmospheric pressure, which varies with altitude and weather. Psi means pound-force per square inch. Display rounding can substantially affect the relative precision of small results, so retain additional digits when needed for engineering calculations. No supported input range or general display-precision rule is specified beyond the supplied example.
Common questions
Why does 1 pascal display as 0.00001 atmosphere?+
One standard atmosphere equals exactly 101325 pascals, so 1 pascal is approximately 0.000009869232667 atmosphere. Rounded to five decimal places, that becomes 0.00001 atmosphere.
Are bar and atmosphere the same pressure unit?+
No. One bar equals exactly 100000 pascals, while one standard atmosphere equals exactly 101325 pascals. Selecting bar instead of atmosphere therefore produces a different numerical result for the same pressure.
Does converting psi to pascal turn gauge pressure into absolute pressure?+
No. A gauge-pressure input remains gauge pressure after conversion, and an absolute-pressure input remains absolute pressure. Converting gauge pressure to absolute pressure requires adding the relevant ambient pressure separately.
Does the atmosphere option adjust for my altitude?+
No. It uses the fixed standard-atmosphere unit, not a measurement or estimate of local air pressure. Altitude and weather do not alter this unit conversion factor.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.