E6B Flight Computer in Your Browser
Date Published
Try it now: Open the E6B Flight Computer →
If you have ever done IFR flight planning, you know the E6B. The original is a circular slide rule made of aluminum that pilots have been spinning around since the 1940s. There is also the electronic version, a chunky calculator that lives in a flight bag and does the same math faster. Both work great, but I wanted something I could open on any device, get an answer in seconds, and — most importantly — actually see the math behind the answer. So I built one.
The tool covers seven calculators: the wind triangle (heading and ground speed, or find the wind from what you actually flew), time/speed/distance with ETA calculation, fuel planning with reserves, density altitude and true airspeed, runway wind components, descent profile planning, and a unit converter for distances, speeds, pressures, volumes, weights, and temperatures. Every result comes with a step-by-step breakdown showing the formula and the numbers plugged in. If you want to understand why your density altitude is 2,000 feet above your indicated altitude on a hot day, the working is right there.
The wind triangle
The wind triangle calculator is the heart of the E6B. Give it a true course, your true airspeed, and the winds aloft forecast, and it tells you the heading to fly and the ground speed you will make good. It also runs in reverse: enter the heading you actually flew, your TAS, the track you made good over the ground, and your GPS ground speed, and it works backward to find the actual wind. Both modes draw the vector diagram so you can see the triangle close up. Magnetic variation converts your true heading to the one you set on the heading bug.
Density altitude and the hot day surprise
The density altitude tab is one I reach for most on hot days. On a 95-degree summer afternoon at a high-elevation airport you might be at 4,500 feet indicated but performing like you are at 7,500. The calculator computes it properly using the ISA model, shows you the ISA deviation, and gives true airspeed for any calibrated airspeed input. It flags a warning if the deviation is over 10 degrees — that is when you really need to look at your performance charts carefully.
Runway crosswinds
The runway wind tab decomposes any wind into headwind and crosswind components, handles gusts separately, and tells you whether you are within your aircraft crosswind limit and by how much. The diagram draws the runway with wind arrows so you can see the geometry. Tower and ATIS winds are magnetic; METAR winds are true — the tool reminds you so you use the right reference.