How to Calculate Wind Correction Angle and Ground Speed

Q: Is the wind triangle calculator free?

Yes, without limits. Only the Analogue E6B wheel is metered, with 3 free opens.

What the wind triangle gives you

Three things you already have for each leg: true course off the chart, true airspeed from the POH, and the forecast wind. The wind triangle turns those three into the heading to actually fly and the ground speed you'll make, and from ground speed you get time and fuel for free.

The wind correction angle formula

Angle = wind direction − true course.
Crosswind = wind speed × sin(angle); headwind = wind speed × cos(angle).
Wind correction angle = asin(crosswind ÷ TAS). True heading = true course ± that angle, into the wind.
Ground speed = TAS × cos(wind correction angle) − headwind.

60 ÷ TAS × crosswind gives degrees of correction in your head: 60 ÷ 110 × 15 ≈ 8°, close enough for a sanity check mid-flight. Not a substitute for the planned figure, just a way to notice when the planned figure is wrong.

How to calculate it in E6B Calc

On E6B, open Wind Triangle under Flight.
Type the True course in degrees from your chart.
Type the True airspeed for the leg.
Enter Wind from in degrees true and Wind speed. Forecast winds aloft are already true.
Read True heading, Ground speed and Wind correction angle, plus Head/tailwind and Crosswind. The rose shows course, wind and heading.

Worked example: from true course to compass heading

One navlog leg worked in E6B Calc
Step	Input	Result
Wind Triangle	True course 090°, TAS 110 kt, wind 040° at 20 kt	True heading 082°, ground speed 96 kt, WCA 8° left
Components	Same leg	13 kt headwind, 15 kt crosswind from the left
Magnetic & Compass	082 °T, variation −10 (10° W), deviation +2	092 °M, 090 °C
Time · Speed · Distance	96 kt over 120 nm	1 h 15 min

Variation and deviation in row three are invented for the example — pull your own variation from the isogonic line on the chart and deviation from the compass card bolted near your aircraft's compass. Magnetic & Compass takes east as positive, west as negative: "east is least, west is best," if that mnemonic has stuck for you.

How to use the E6B wind side, the analogue way

Still learning the mechanical wheel? The Analogue E6B screen simulates the wind side: turn the azimuth card with a finger to put the course under the index, then set Wind from, Wind speed and True airspeed with sliders. Same heading, ground speed and correction come out as on the digital screen, and How to use the wheel walks each step. It has 3 free opens before E6B Pro; the digital Wind Triangle has none.

Common mistakes

Mixing true and magnetic: a true course needs a true wind. Convert to magnetic only after you have the true heading.
Correcting the wrong way: always turn into the wind. Wind from the left means a heading less than the course.
Using indicated airspeed instead of true airspeed at cruise altitude. Work out TAS first.
Expecting it to find the wind: the screen solves course to heading only. It cannot work out an unknown wind from heading, track and ground speed.

When the crosswind is stronger than your airspeed, or the headwind stops you, the app shows No solution instead of a number.

Questions and answers

How do I find true heading on an E6B?

On the wind side, set the wind, put the true course under the index and the TAS under the grommet, then read the correction angle and apply it into the wind. The app's Wind Triangle gives the same true heading directly.

What is a wind correction angle in a hold?

It is the same crab angle applied to the holding legs. E6B Calc's Holding Entry does not add wind correction, so work it out separately with the Wind Triangle if you want a planned figure.

Can the app find the wind from my heading and ground speed?

No. It solves the forward problem only: course, TAS and wind in, heading and ground speed out.

Is the wind triangle calculator free?

Yes, without limits. Only the Analogue E6B wheel is metered, with 3 free opens.

How to calculate wind correction angle, true heading and ground speed