Hi All, I am after an opinion on the following.: (hopefully it makes sense) forgive me if the jargon is wrong I am interested only in theory. I am not taking into account mapreading, ATIS, cold fronts, warm fronts, local QNH, area QNH or any other variables, it is purely a difference in altitude of airfields and indicated AGL V's actual AGL. NOTHING ELSE MATTERS FOR THIS PURELY HYPOTHETICAL QUESTION I take off from airfield (A) which I know is at an elevation of 0' (sea level). and have set altimeter accordingly to read 0' I fly to airfield (B) which I know is at an elevation of 1000' ASL Hypothetically, on arrival at (B) if I join circuit at 1000' as indicated by my altimeter I am 1000 AMSL but only 0' AGL (obviously wrong), I therefore have to think about it, do some math and climb to 2000' indicated to give me my circuit height (1000'AGL) OR: Do I somewhere along the flight path readjust altimeter by subtracting 1000' (Difference between A+B) by turning knob, to accommodate known altitude of airfield (B) therebye joining circuit at 1000' AGL and 1000' indicated on alt (2000' ASL in fact) without having to do math at landing stage, relieving my workload .