# Help..... Millibar to QNH conversion

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Howdie Folks,Can anyone give me a guideline how to convert the altimeter millibar reading to QNH? There must be a conversion chart or something available somewhere, but at this time i have come up with nothing.Thanks http://www.avsim.com/vfr_center/avsim_sig.jpg

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Hi, the chart is correct, but 1 hPa (Hektopascal, 100 Pascal) equals 0.02953 in Hg (1 bar = 10^5 Pa).Best Regards, Uwe Rademacherhttp://www.avsim.com/pss/phoenix.jpg

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> There must be a conversion chart or something available somewhere, but at this time i have come up with nothing. >Assuming what you want is a conversion chart from millibars (hectopascals) to inches of mercury, (and vice versa) there's one in the AVSIM library! Search for "presconv.zip".Pete

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example29.92 X 33.85 = 1012.7 or 1013 QNH

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use this thumb rule freind ,works both ways ,and is very accurate .CONVERT MILLIBARS TO IN HG AND VICE VERSA IF IN MBS-- FIND THE DIFF BETWEEN QNH GIVEN AND 1013 , MULTIPLY THE DIFF BY 3 , THEN ADD OR SUBTRACT TO 29.92 AS REQUIRED , ie IF GIVEN QNH IS ABOVE OR BELOW 1013EG 1000 MBS ,SO 1013 - 1000 = 13 ,AND 13 * 3 = 39NOW 29.92 -0.39 (BECAUSE 1000 IS LESS THAN 1013)= 29.53..REVERSE THE PROCESC WHEN U GOTTA CONVERT INS TO MBS ,U JUST DIVIDE..lemme know if it worked for u..bi bi kunal

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Hello Aidan,I guess that you were looking for a conversion method for Inches of Mercury vs. Millibars (Hectopascal).The QNH is the Mean Sea Level barometric pressure based on the local field pressure corrected for elevation difference (on the basis of 1mb for each 30 feet of difference). An altimeter set on QNH will show you the altitude above mean sea level.The QNE is the standard pressure (29.92" or 1013.2mb)and it gives you a reading of "pressure altitude" (the altimeter reading at the standard baro. pressure).The QFE is the barometric pressure at the local station (airfield). An altimeter calibrated at QFE will show the altitude above the airfield.Hope this will help.Cheers,twister

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Oops, that's what you get for copying from a website without checking, gotta watch that decimal point! Thanks for the correction Uwe.

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