how do you convert millibars to inches?
1 millibar (or hectopascal/hPa), is equivalent to 0.02953 inches of mercury (Hg). It is therefore only necessary to multiply a reading in millibars by the latter figure, to achieve the required conversion. E.g. for 1023 mbar, multiply by 0.02953=30.21 inches. To go the other way, the relationship is 1 inch of mercury=33.8639 mbar; again as an example, to convert 29.45 inches, multiply by 33.8639=997 mbar.