QNH, QFE and the altimeter setting

An altimeter measures pressure, not height. Which number it shows depends on the reference pressure you give it – and for VFR flights in Germany that is expressly regulated.

Applicability: Reporting format: European Union (EASA framework). Setting rule: Germany
Rulemaking authority: Commission Implementing Regulation (EU) 2017/373 (reporting of pressure); AIP VFR Germany ENR 1-14 (altimeter setting on VFR flights)
Reviewed by NorthTrack on: 2026-09-13

The three reference pressures

QNH
Reference: atmospheric pressure reduced to mean sea level · The altimeter then shows: altitude above MSL – so at the aerodrome, its elevation
QFE
Reference: atmospheric pressure at the aerodrome reference point · The altimeter then shows: height above the aerodrome – so zero on the ground
1013.2 hPa
Reference: standard atmosphere · The altimeter then shows: a pressure altitude, expressed as a flight level

In Germany QNH is the practical working basis. QFE plays almost no part in national operations and does not appear in a METAR in any case: the Regulation provides that METAR and SPECI contain QNH values only. QFE appears only in local reports, and even there only where it is required.

The altimetry abbreviations

These abbreviations decide what an altitude figure is referenced to — and therefore whether it can be compared with the terrain.

QNH — Atmospheric pressure reduced to MSL by ICAO Standard Atmosphere and altimeter sub-scale setting to obtain aerodrome elevation when on the ground
The altimeter then shows altitude above mean sea level; on the ground at an aerodrome, that aerodrome's elevation.
QFE — Atmospheric pressure at aerodrome elevation (or at runway threshold)
The altimeter shows height above the aerodrome; zero on the ground. QFE does not appear in a METAR.
STD — Standard (altimeter setting)
1013.2 hPa — to be set above the applicable limit.
ALT — Altitude
The reference is mean sea level; the setting is QNH.
HGT — Height or height above
The reference is the terrain or the aerodrome.
AMSL — Above mean sea level
Used on the aeronautical chart and in the AIP.
MSL — Mean sea level
The reference surface for heights above the sea.
AGL — Above ground level
The reference is the terrain directly below.
AAL — Above aerodrome level
Cloud heights in a METAR are referenced to the aerodrome elevation.
ELEV — Elevation
The elevation of the aerodrome above mean sea level.
FL — Flight level
A pressure surface referenced to 1013.2 hPa — not a height above the ground.
hPa — Hectopascal
The unit of atmospheric pressure; QNH is reported as four digits in whole hPa.

How QNH is reported

QNH is calculated in tenths of a hectopascal and reported in whole hectopascals as four digits.
Values that do not fit the increment are rounded down.
A reported Q1013 can therefore correspond to as much as 1,013.9 hPa – the rounding works in favour of safety, because it makes the indicated altitude read low rather than high.

The German rule for VFR flights

AIP VFR Germany ENR 1-14
On flights under visual flight rules up to an altitude of 5,000 ft MSL, or up to a height of 2,000 ft AGL where that flight altitude exceeds 5,000 ft MSL, the altimeter is to be set to the QNH of the nearest aerodrome with an air traffic control unit along the route. Above those altitudes the altimeter is to be set to 1013.2 hPa.

The second half of that sentence is often skipped over. It bites in mountainous country: where the terrain is high enough that 2,000 ft above ground already lies above 5,000 ft MSL, the QNH stays set up to that higher limit. Without the rule you would be flying on standard pressure at low height above the ground in the mountains.

Why the QNH should come from the nearest aerodrome

Pressure changes along the route. A QNH from the departure aerodrome does not stay correct as you fly – flying into an area of low pressure, the altimeter over-reads, so the aircraft is lower than the instrument claims. The rule to use the QNH of the nearest aerodrome with an ATC unit is what bounds that error.

The mnemonic
From high pressure to low, or from warm to cold: the altimeter over-reads and the aircraft is lower than indicated. The error works in the direction that is unfavourable for terrain and obstacles.

Temperature

Even with the QNH correctly set, the indicated altitude is only right in the standard atmosphere. At temperatures below standard the true height above the ground is less than indicated. For minimum altitudes in winter and for obstacle clearance this is a separate, additional effect – not the same as the pressure error.

Pressure altitude, density altitude and ISA deviation can be tried out directly in the NorthTrack calculators. Open Aviation Tools

Official sources

DFS Deutsche Flugsicherung GmbH: Aeronautical Information Publication Germany – AIP VFR – Effective 20 AUG 2026. Open source (retrieved 2026-09-13)
DFS Deutsche Flugsicherung GmbH: Aeronautical Information Publication Germany – AIP VFR, GEN 2-1 to GEN 2-7 "Abkürzungen / Abbreviations" (bilingual German/English) – Effective 20 AUG 2026. Open source (retrieved 2026-09-13)
European Commission / EASA: Commission Implementing Regulation (EU) 2017/373 (Annex V "Part-MET", Annex VI "Part-AIS") – Consolidated version 02017R0373-20250501. Open source (retrieved 2026-09-13)
Deutscher Wetterdienst (DWD), the German national meteorological service: METAR / TREND / TAF – aviation weather reports and forecasts (bilingual code tables) – DWD 134, edition 01/2024. Open source (retrieved 2026-09-13)