Convert common pressure units without losing a factor of ten or one thousand.
Core idea
The core relationships are 1 bar = 1000 millibar and 1 bar = 100 kilopascal. Therefore 1 kilopascal = 10 millibar. Write the relationship first, then decide whether the numerical value should become larger or smaller in the new unit.
What to recognise
- Convert bar to millibar by multiplying by 1000.
- Convert millibar to bar by dividing by 1000.
- Convert bar to kilopascal by multiplying by 100.
- Convert kilopascal to millibar by multiplying by 10.
- Keep gauge and absolute pressure descriptions separate when the context uses them.
Apply it
For 1.5 bar: 1.5 × 1000 = 1500 mbar and 1.5 × 100 = 150 kPa. For 21 mbar: 21 ÷ 1000 = 0.021 bar and 21 ÷ 10 = 2.1 kPa. A quick magnitude check catches most errors.
Keep the boundary clear
A correct unit conversion does not establish a safe test pressure or operating limit. Use the procedure, instrument range, resolution and manufacturer data for the actual system. Never substitute bar for millibar in a gas procedure merely because both are pressure units.
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