Aviation unit converter
Convert pressure, visibility, wind speed, altitude, temperature, weight and fuel between the units you find in METARs, TAFs and flight planning.
Pressure (QNH / altimeter)
hPa and millibar (mb) are the same. US and Canadian METARs give the altimeter in inHg (A2992 = 29.92 inHg).
- 29.92
- inHg
- 760
- mmHg
Distance & visibility
METAR visibility is in metres (9999 = 10 km or more), or statute miles in the US. Navigation distances are in nautical miles.
- 5,000
- m
- 2.7
- NM
- 3.11
- sm
- 16,404
- ft
Speed & wind
Wind is reported in knots almost everywhere. Some stations use MPS (m/s), for example in Russia and China.
- 27.8
- km/h
- 7.7
- m/s
- 17.3
- mph
- 1,519
- ft/min
Altitude & height
A flight level is pressure altitude in hundreds of feet with 1013.25 hPa set (FL95 = 9,500 ft). It equals true altitude only in standard conditions.
- 914
- m
- 30
- FL
Temperature
METARs report °C, with M for minus (M05 = −5 °C). ISA at sea level is 15 °C.
- 59
- °F
- 288.2
- K
Weight
- 220.5
- lb
Volume
- 26.4
- US gal
- 22
- Imp gal
Fuel: volume to weight
Uses a typical density of 0.72 kg/L. Real density changes with temperature, so use the figure from your fuel receipt for weight and balance.
- 26.4
- US gal
- 22
- Imp gal
- 72
- kg
- 158.7
- lb
Frequently asked questions
How do I convert hPa to inHg?
Divide hPa by 33.8639. Standard pressure 1013.25 hPa equals 29.92 inHg. To go from inHg to hPa, multiply by 33.8639.
How many kilometres is a nautical mile?
One nautical mile is exactly 1.852 km. A statute mile is 1.609 km. One knot is one nautical mile per hour, about 1.852 km/h or 0.514 m/s.
How heavy is a litre of Avgas or Jet A-1?
Typically about 0.72 kg per litre for Avgas 100LL (6 lb per US gallon) and about 0.80 kg per litre for Jet A-1 (6.7 lb per US gallon), at 15 °C. Density varies with temperature.
What is a flight level in feet?
A flight level is pressure altitude in hundreds of feet with the altimeter set to 1013.25 hPa (29.92 inHg). FL95 is 9,500 ft and FL350 is 35,000 ft on the standard setting.