Crosswind and Headwind Calculator for Runways

How to use it

Choose Runway given as: Heading in degrees, or Runway number for the number painted on the runway.
Type the runway in Runway heading (degrees) or Runway number (1 to 36). Runway 27 is heading 270.
Type the wind in Wind direction (degrees), where it comes from, and Wind speed (kt). Add Gust speed (kt) if the report gives one.
Type the Demonstrated crosswind (kt) from your aircraft's flight manual to compare it. Then read the crosswind, the headwind or tailwind, and the verdict.

How the components are found

The runway and the wind are two directions on a compass. The calculator takes the angle between them: the wind direction minus the runway heading, written from -180 to +180 degrees. A positive angle means the wind comes from the right of the runway; a negative angle means it comes from the left.

Part of the wind speed acts across the runway and part of it acts along the runway. The sine of the angle gives the crosswind, and the cosine gives the headwind.

crosswind = V × sin(a)
headwind = V × cos(a)

V  wind speed in knots
a  wind direction minus runway heading, from -180 to +180 degrees

A positive crosswind comes from the right and a negative one from the left. The size of the crosswind is what is compared with the demonstrated crosswind.
A positive headwind blows into the nose. A negative headwind is a tailwind.
A calm wind (speed 0) has no components on any runway.

What the calculator does not cover

This page is for training and planning practice, not for real flight. For a real flight, use your aircraft's flight manual for its demonstrated crosswind and approved wind limits, and the current weather from an official source.

Landing technique: the crab, wing-low and side-slip methods, the control inputs, and the decision to go around or divert. The page gives the numbers, not the technique.
Gusts: the gust results are the same calculation with the gust speed. The tool applies no gust factor and adds no margin, and the verdict compares only the steady crosswind with the limit.
The aircraft limit: the demonstrated crosswind is the value you type from the manual. The tool does not know your aircraft, its weight or your experience.
Turbulence, wind shear, changes of wind near the ground, and obstacles that change the wind on the approach.
Runway condition: a wet, icy or contaminated runway can change how much crosswind is safe, and the tool does not consider the surface.

Where the method comes from

The FAA Pilot's Handbook of Aeronautical Knowledge, chapter 16 (Navigation), explains the wind triangle as a graphic explanation of the effect of wind upon flight, and defines the wind correction angle in degrees right or left of the course. The runway picture used here is the same vector picture.

The Airplane Flying Handbook (FAA-H-8083-3C) says that the headwind and crosswind components are determined by reference to a crosswind component chart, and that pilots must determine the maximum crosswind component of each airplane they fly. Its glossary defines the crosswind component as the wind component, measured in knots, at 90 degrees to the longitudinal axis of the runway.

Neither handbook gives the sine and cosine formula. The formula used here is the vector resolution of the wind along and across the runway: the sine and cosine of the angle between the wind and the runway. It is a mathematical identity, not a formula quoted from an FAA source.

Worked example: runway 27 with wind from 300 at 20 kt

The page opens with this case: runway given as heading 270, wind direction 300, wind speed 20 kt, gust speed 28 kt and a demonstrated crosswind of 15 kt.

The angle is 300 − 270 = 30 degrees, so the wind comes from the right. The crosswind is 20 × sin 30° = 10.0 kt from the right, which is within the 15 kt limit. The headwind is 20 × cos 30° = 17.3 kt. With the 28 kt gust, the gust crosswind is 14.0 kt from the right and the gust headwind is 24.2 kt.

Result	Value
Crosswind	10.0 kt from the right
Headwind	17.3 kt
Gust crosswind	14.0 kt from the right
Gust headwind	24.2 kt
Verdict	Within the demonstrated crosswind.

Frequently asked questions

Which way does the wind direction point?

It is the direction the wind comes from, as on a compass: 360 is north, 90 is east, 180 is south and 270 is west. A wind from 300 comes from the west-north-west, so on runway 27 (heading 270) it is 30 degrees to the right.

Is a crosswind from the left as bad as one from the right?

The calculator compares the size of the crosswind with your demonstrated limit, whichever side it comes from. The side tells you which way the wind will push the aircraft, and the correction you use for it is what your flight training teaches.

What is the demonstrated crosswind?

It is the highest crosswind component the aircraft was shown to handle during flight testing, and the manufacturer lists it in the flight manual or pilot's operating handbook. The Airplane Flying Handbook tells pilots to determine it for each airplane they fly.

Does a higher gust change the verdict?

Not in this calculator. The gust crosswind and gust headwind are calculated and shown, but the verdict compares only the steady crosswind with your limit. Check the gust crosswind yourself against the same limit before you plan a landing.

Why does runway 36 give 360 degrees and runway 1 give 10?

A runway number is the heading divided by ten: runway 36 points north at heading 360, and runway 1 points to heading 010. The calculator works from the heading, so 27L and 27 give the same result.

Can I use this page to plan a real flight?

No. The calculator is for training and planning practice. For a real flight, use your aircraft's flight manual, its approved wind limits, and the current weather from an official source.

Sources

Figures and text last checked on Tuesday, November 10, 2026.