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Aviation Unit Converter
Instantly convert speed (knots, km/h, mph, Mach), altitude (feet, meters, flight levels), and temperature (°C, °F, Kelvin) — all in one place for pilots, AMEs and dispatchers.
Speed Converter
KT
km/h
mph
m/s
ft/min
Mach
FL / ft
Mach conversion uses ISA temperature at the given altitude. Speed of sound ≈ 661 kt at sea level (15°C).
Altitude / Flight Level Converter
ft
m
FL
km
nm
Flight Level Note
FL is pressure altitude in hundreds of feet (QNH 1013.25 hPa / 29.92 inHg). FL350 = 35,000 ft pressure altitude.
FL is pressure altitude in hundreds of feet (QNH 1013.25 hPa / 29.92 inHg). FL350 = 35,000 ft pressure altitude.
Temperature Converter
°C
°F
K
°R
Aviation Reference Temps
| ISA Sea Level | 15°C / 59°F / 288.15 K |
| ISA Tropopause (36,089 ft) | −56.5°C / 216.65 K |
| Water freezing point | 0°C / 32°F / 273.15 K |
| Jet A-1 freeze point | −47°C |
Common Speed References
| Speed Context | Knots (kt) | km/h | mph |
|---|---|---|---|
| Typical approach (light AC - e.g. C172) | 65 | 120 | 75 |
| Typical approach (jet - Vref) | 140 | 259 | 161 |
| Typical cruise (turboprop) | 280 | 519 | 322 |
| Typical cruise (narrow-body) | 450 | 833 | 518 |
| Mach 0.80 @ FL350 (Standard Temp) | 459 | 850 | 528 |
| Speed of sound (Sea Level, ISA) | 662 | 1,225 | 761 |
Common Altitude References
| Altitude Context | Feet (ft) | Metres (m) | Flight Level (FL) |
|---|---|---|---|
| Transition altitude (EASA typical) | 6,000 | 1,829 | FL060 |
| Typical turboprop cruise | 25,000 | 7,620 | FL250 |
| Typical narrow-body cruise | 35,000 | 10,668 | FL350 |
| Typical wide-body cruise | 39,000 | 11,887 | FL390 |
| Tropopause (ISA) | 36,089 | 11,000 | FL361 |
| Service ceiling (B747-400) | 45,100 | 13,747 | FL451 |
Frequently Asked Questions
IAS (Indicated Airspeed) is what the airspeed indicator reads. TAS (True Airspeed) is the actual speed through the air mass, accounting for altitude and temperature. GS (Ground Speed) is TAS corrected for wind. This converter works with TAS/GS values.
Mach = TAS ÷ Local Speed of Sound. The local speed of sound depends on temperature: a = 38.967 × √T (K) in knots. In ISA conditions, the lapse rate is −1.98°C per 1,000 ft up to the tropopause.
A Flight Level is a pressure altitude expressed in hundreds of feet, with the altimeter set to standard pressure (1013.25 hPa / 29.92 inHg). FL350 = 35,000 ft pressure altitude. FLs are used above the transition altitude to ensure vertical separation between aircraft.