To convert one non-pascal pressure unit to an alternative non-pascal unit, multiply the 'starting' pressure value by the 'number of pascals' shown against its unit (in the Pressure Units table) and then divide the product by the number of pascals shown against the second unit.

The third and fourth examples below illustrate how extra precision (more significant figures) can be erroneous and misleading rather than conveying greater accuracy:

Example 1: Convert mbar to pascals

Example 2: Convert inches of mercury to kilogram-force per square centimetre

... and some examples containing meaningless over-precision:

Example 3: Convert two similar values of millimetres of mercury to pascals

Example 4: Convert pascals to pound-force per square inch