Kite Altitude Calculator
Calculate kite altitude from line length and angle.
Find horizontal distance, actual altitude reached, and view results across all angles.
Kite Altitude — The Trigonometry
When a kite flies, the string, the altitude, and the horizontal distance form a right triangle. The string is the hypotenuse, altitude is the vertical side, and horizontal distance is the base. Basic trigonometry gives exact results from line length and angle alone.
The formulas:
- Altitude = line length × sin(angle)
- Horizontal distance = line length × cos(angle)
- Angle is measured from the horizontal ground up to the kite line
What angle to expect
Most single-line delta kites fly between 40° and 70° in steady breezes. A lower angle (30–45°) typically means the wind is lighter or the kite needs more tail weight. A higher angle (65–80°) means the wind is strong and the kite is climbing efficiently. At exactly 45°, altitude equals horizontal distance — a useful field rule of thumb.
Example results at 100 m of line:
| Angle | Altitude | Horizontal Distance |
|---|---|---|
| 30° | 50 m | 86.6 m |
| 45° | 70.7 m | 70.7 m |
| 60° | 86.6 m | 50 m |
| 75° | 96.6 m | 25.9 m |
Altitude limits by country
- United States (FAA): Kites must stay below 150 m (500 ft) AGL in uncontrolled airspace without authorization.
- United Kingdom (CAA): Maximum 60 m (197 ft) without authorization.
- Australia (CASA): Maximum 122 m (400 ft) AGL without a permit. Always check local aviation regulations before flying near airports or flight paths.
Measuring line angle in the field
A clinometer or smartphone inclinometer app gives an accurate angle reading. Hold the phone along the kite line and read the angle from horizontal. Most experienced fliers can estimate within 5° by feel after regular practice.
How wind affects the calculation
This calculator assumes a straight, taut line — the ideal case. In practice, kite lines sag slightly from their own weight, especially with longer lines. The actual altitude will be a few percent lower than calculated for lines over 100 m. A heavier line sags more; a lighter braided polyester or Dyneema line sags less.