flight level (FL) to feet Converter
Convert flight level (FL) to feet instantly with a reference conversion table.
| flight level (FL) | feet |
|---|
How to convert flight level (FL) to feet
Enter your value
Type the number of flight level (fl) you want to convert into the left box. The result in feet appears instantly in the right box. You can also type into the right box to convert in the other direction.
Use the swap button
Click the ⇄ Swap button to reverse the conversion — feet to flight level (FL). Your current value carries across so you don't have to re-enter anything.
About flight level (FL) and feet
Flight levels are defined directly in hundreds of feet, so converting flight level to feet is simply multiplying by 100 -- there's no separate unit-conversion factor involved, unlike converting to meters. The number itself represents pressure altitude (measured against a standard reference pressure of 1013.25 hPa), not necessarily the aircraft's true height above the ground.
Flight levels and feet in real-world aviation
Reading ATC clearances and cruise altitudes
Air traffic control communicates cruising altitude almost exclusively as a flight level once an aircraft climbs above the transition altitude ("climb and maintain FL350"). Converting to feet is useful for pilots cross-referencing performance charts, weight-and-balance calculations, or older documentation that specifies altitude in feet rather than flight level.
Why cruise altitude sits so high
Commercial jets cruise at FL310-FL410 (31,000-41,000 feet) mainly to fly above most weather and turbulence while benefiting from thinner air that reduces drag and improves fuel efficiency. This is well above the altitude humans can breathe unassisted, which is why cabins are pressurized to an equivalent of roughly 6,000-8,000 feet even at these cruising flight levels.
Flight level feet vs true altitude feet
Because a flight level's "feet" value is calculated against a standard pressure setting rather than actual local conditions, it can differ slightly from the aircraft's true height above sea level on days with unusual pressure or temperature. This distinction matters most for terrain clearance calculations at lower altitudes and in extreme cold, where pilots apply correction charts to the nominal flight-level feet figure.
| flight level (FL) | feet |
|---|---|
| 100 | 1e+04 |
| 200 | 2e+04 |
| 300 | 3e+04 |
| 350 | 3.5e+04 |
| 370 | 3.7e+04 |
| 390 | 3.9e+04 |
Frequently asked questions
How do I convert flight level (FL) to feet?
To convert flight level (FL) to feet, multiply by 100. Or use the calculator above for instant results.
How many feet are in 1 flight level (FL)?
1 flight level (FL) equals 100 feet.
Is the flight level (FL) to feet converter free?
Yes, the flight level (FL) to feet converter is completely free with no sign-up required, no downloads, and it works offline once the page has loaded.
Why is the flight level to feet conversion just multiplying by 100?
Flight levels were defined from the start as hundreds of feet, so FL350 literally means 35,000 feet by definition — no separate conversion factor is involved, unlike converting to meters.
Is a flight level's feet value the same as true altitude in feet?
Not necessarily. A flight level's feet value is pressure altitude, calculated from a standard 1013.25 hPa reference, while true altitude is actual height above sea level. These can differ slightly when local pressure varies from the standard.
What feet altitude marks the switch from altitude to flight levels?
The transition altitude varies by country, from around 3,000 feet in parts of Europe up to 18,000 feet across the continental US. Below it, altitude is given in feet; above it, everyone uses flight levels.
Why do commercial jets cruise at such high flight levels?
Cruising at FL310-FL410 puts aircraft above most weather and turbulence, and thinner air reduces drag and improves fuel efficiency. Cabins are pressurized to an equivalent of roughly 6,000-8,000 feet even at these altitudes.