Induced Drag Coefficient Calculator

The unavoidable price of generating lift

Induced drag is caused by wingtip vortices that form whenever a wing generates lift - unlike parasitic drag from skin friction and pressure, induced drag cannot be eliminated by streamlining alone, only reduced through wing design.

Worked example

For a wing with a lift coefficient of 1.2, an aspect ratio of 7.5, and an Oswald efficiency factor of 0.85 (a typical real-world value accounting for non-ideal lift distribution):

CDi = 1.2² / (π x 7.5 x 0.85) = 0.0719

Frequently asked questions

What is the Oswald efficiency factor? It is a correction factor (typically 0.7-0.9 for real aircraft) accounting for the fact that real wings do not achieve the theoretically ideal elliptical lift distribution that a perfect wing of the same aspect ratio would produce.

Why does induced drag matter most at low speed? Since CDi scales with the square of the lift coefficient, and lift coefficient must rise as speed falls to maintain the same total lift, induced drag increases sharply at low speeds - this is exactly why aircraft feel most affected by induced drag during takeoff, climb, and landing, while parasitic drag dominates at high cruise speeds.