Read the number of bars to be converted on a barometer. Make sure your units are correct -- barometers can be marked in either bars or Pascals, and starting with the incorrect units will prevent you from making a proper calculation.
Multiply the number of bars by 100,000. The product of the multiplication is your final number of Pascals. For example, 6.5 bars equals 650,000 Pascals.
Divide the number of Pascals by 1,000 to reduce your answer to a more manageable number. The number of Pascals is likely to be quite large, so converting from Pascals to kilo-Pascals will simplify your answer.