Wind Triangle Calculator
Enter your course, airspeed and the wind to get the heading to fly, the wind correction angle and your ground speed, with a live vector diagram.
The line you want to fly over the ground, from your chart.
The way the nose points.
Where the wind blows from, as in a forecast or METAR.
Winds-aloft forecasts, TAFs and METARs give true directions. ATIS and the tower give magnetic. Chart courses are true unless measured from a VOR or compass rose.
From the chart (isogonic lines). East is least, west is best.
From the compass card in your aircraft, for this heading.
Each leg uses the units, variation, deviation and fuel burn above. Leave a leg's TAS blank to use the main TAS. Courses follow your true / magnetic choice; leg winds follow the wind choice.
How your heading and ground speed are worked out
Split the wind into a crosswind and a headwind, turn into the crosswind just enough to cancel it, then take off the headwind.
- 1
Angle to the wind
wind 030° − 090°= 60° off the nosefrom the left
- 2
Split the wind (kt)
20 × sin 60° = 17.320 × cos 60° = 10.0cross left, head
- 3
Turn into it
asin(17.3 ÷ 120)= 8.3° leftheading 082°
- 4
Ground speed
120 × cos 8.3°− 10.0 headwind= 109 kt
Read more: the formula, a worked example, variation, deviation and the flight log
An aeroplane flies through the air, and the air itself moves over the ground. To follow a line on the chart you point the nose a little into the wind, and your speed over the ground is your airspeed plus or minus the part of the wind along your path. Drawn as arrows, the air vector (heading and TAS), the wind vector and the ground vector (track and ground speed) make a triangle: the wind triangle that an E6B flight computer solves.
The formula
wind angle = wind direction − true course
crosswind = wind speed × sin(wind angle) (+ from the right)
headwind = wind speed × cos(wind angle) (− means tailwind)
wind correction angle = arcsin(crosswind ÷ TAS)
true heading = true course + wind correction angle
ground speed = TAS × cos(wind correction angle) − headwind
magnetic = true − east variation (+ west variation)
compass = magnetic − east deviation (+ west deviation)
leg time = distance ÷ ground speed; fuel = time × burn per hour
Worked example
You want a true course of 090° at a TAS of 120 kt, and the wind is from 030° at 20 kt. The wind angle is 030 − 090 = −60°, so the wind is 60° off the nose from the left. The crosswind is 20 × sin 60° = 17.3 kt from the left and the headwind is 20 × cos 60° = 10 kt.
The wind correction angle is arcsin(17.32 ÷ 120) = arcsin(0.1443) = 8.3° left, so the true heading is 090 − 8.3 = 81.7°, which you fly as 082°. The ground speed is 120 × cos 8.3° − 10 = 118.74 − 10 = 109 kt (108.74).
The Advanced example adds 5° east variation and 2° west deviation: the magnetic heading is 81.7 − 5 = 76.7, flown as 077°, and the compass heading is 76.7 + 2 = 78.7, flown as 079°. A 150 nm leg takes 150 ÷ 108.74 = 1.379 hours, which is 1 h 23 min, and at 9 US gallons an hour burns 1.379 × 9 = 12.4 US gallons. With no wind it would take 150 ÷ 120 = 1 h 15 min, so the wind costs you 8 minutes.
The four problems
- Heading and ground speed: the everyday planning sum. You know the course, TAS and forecast wind.
- Track and ground speed: you hold a heading and want to know where the wind will take you.
- The wind: in flight, read heading and TAS from the instruments and track and ground speed from the GPS. The difference between the two arrows is the actual wind.
- Airspeed needed: the TAS and heading that give a ground speed you want, for example to arrive on time.
True, magnetic and compass
Wind triangles are solved in true directions, because forecasts and charts are true. Then convert: true heading ± variation = magnetic heading, magnetic ± deviation = compass heading. East is subtracted and west is added ("east is least, west is best"). If you enter a magnetic course or a magnetic wind (from ATIS), the calculator turns it into true first, using your variation.
| Step | Example |
|---|---|
| True course | 090° |
| ± wind correction | 8.3° left → 081.7° true heading |
| ± variation (5° E) | − 5 → 076.7° magnetic heading |
| ± deviation (2° W) | + 2 → 078.7° compass heading |
Handy rules of thumb
- The largest drift any wind can cause is about wind speed ÷ (TAS ÷ 60) degrees. At 120 kt that is 2 kt a minute, so 20 kt of wind can push you up to about 10° off.
- A wind 30° off the nose gives about half its speed as crosswind, 45° about 70%, and 60° or more nearly all of it.
- Winds change with height and time. Use the forecast for your cruising level, check your real ground speed on the way and use "find the wind" to update the plan.
For planning and training only. Always check against your own navigation log, forecasts and aircraft instruments. Checked 10 October 2026.
Common questions
How do you calculate wind correction angle?
Work out the crosswind, which is the wind speed times the sine of the angle between the wind and your course. The wind correction angle is the arcsine of that crosswind divided by your true airspeed. With 17.3 kt of crosswind at 120 kt TAS, the correction is about 8.3° into the wind.
How do you find ground speed with wind?
Ground speed is the true airspeed times the cosine of the wind correction angle, minus the headwind component. In the worked example, 120 kt TAS with an 8.3° correction and a 10 kt headwind gives 118.74 minus 10, about 109 kt over the ground. A tailwind adds to it instead.
What is the difference between true, magnetic and compass heading?
Wind triangles are solved in true directions, because charts and forecasts are true. Apply the variation to get the magnetic heading, then the deviation to get the compass heading. East is subtracted and west is added, which pilots remember as east is least, west is best.
How do you find the wind in flight?
Read your heading and true airspeed from the instruments, and your track and ground speed from the GPS. The difference between those two arrows is the actual wind. Choose the find-the-wind problem in the calculator, then use the result to update the rest of your plan.
What is the most drift a wind can cause?
A handy rule is the wind speed divided by how many nautical miles you cover each minute. At 120 kt you cover 2 nm a minute, so 20 kt of wind can push you up to about 10° off. The real drift depends on the angle, and it is greatest when the wind blows straight across.
Does this work like an E6B flight computer?
Yes. It solves the same wind triangle an E6B does: heading and ground speed, track and ground speed, the wind, or the airspeed you need. It also turns true heading into magnetic and compass heading, and works out leg time, fuel and a multi-leg flight log.
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Made by Zulu Calculator, part of AlphaZulu LLC. Formulas are shown in full and rule figures are checked against official sources; see how we build calculators.