Pressure is a scalar quality reflecting how force acts on a surface.
Where P is equal to pressure, F is the normal force and A is area. Since pressure is derived from force and area, many units for pressure directly relate force to area. Some are obvious, such as pounds per square inch, but even the SI standard Pascal is actually an expression of one Newton per square meter.
Conversions are performed by using a conversion factor. By knowing the conversion factor, converting between units can become a simple multiplication problem:
S * C = E
Where S is our starting value, C is our conversion factor, and E is our end converted result.
To simply convert from any unit into pascals , for example, from 5 bar, just multiply by the conversion value in the right column in the table below.
5 bar * 100000 [ (Pa ) / (bar) ] = 500000 Pa
To convert from Pa into units in the left column divide by the value in the right column or, multiply by the reciprocal, 1/x.
500000 Pa / 100000 [ (Pa ) / (bar) ] = 5 bar
To convert among any units in the left column, say from A to B, you can multiply by the factor for A to convert A into Pascals then divide by the factor for B to convert out of Pascals. Or, you can find the single factor you need by dividing the A factor by the B factor.
For example, to convert from bar to pounds per square inch you would multiply by 100000 then divide by 6894.757. Or, multiply by 100000/6894.757 = 14.503774. So, to convert directly from bar to pounds per square inch, you multiply by 14.503774.