The following diagrams will show the methods used to calculate the wing areas for the different shapes of wings. If the area is calculated in square inches, it can be converted to square centimeters by multiplying by 6.45. For instance, a wing area of 698 sq. in. is 4500 cm2. Note that wingtips are normally ignored in calculating the wing area because the area of the tips is fairly insignificant. As a rule of thumb, if the tips appear account for more than 5 percent of the total area and if they have a cross-section of a lifting airfoil, they should be included.

The area of a rectangular wing is the most basic of the calculations. The wing is measured from the centerline to the last rib to get the half-span of the wing. The chord is the straight line distance from the leading edge to the trailing edge including the ailerons. The wing area is calculated by multiplying the half-span by 2 to get the full span and multiplying by the chord to get the area.

span x (root chord + tip chord)/2 = area

Calculating the area of a tapered is only slightly more difficult. The wing is measured from the centerline to the last rib to get the half-span of the wing. The root chord is the straight line distance from the leading edge at the center of the wing to the trailing edge at the center of the wing including the ailerons. The tip chord is the straight line distance from the leading edge at the last rib of the wing to the trailing edge at the last rib of the wing including the ailerons. The wing area is calculated by adding the root chord and the tip chord then multiplying by the half-span.

span x (root chord + tip chord)/2 = area

Calculating the area of a swept back wing would appear to be the most difficult but it is no more difficult than a tapered wing. Visualizing the reason the formula works is probably the most difficult part. The wing is measured from the centerline to the last rib to get the half-span of the wing. The root chord is the straight line distance from the leading edge at the center of the wing to the trailing edge at the center of the wing including the ailerons. The tip chord is the straight line distance from the leading edge at the last rib of the wing to the trailing edge at the last rib of the wing including the ailerons. The wing area is calculated the same way as the tapered wing by adding the root chord and the tip chord then multiplying by the half-span.

More complex wing sections can be calculated by summing the areas of the different wing segments using the examples above to calculate each segment. Some planforms such as the elliptical wing are not covered here because they are too complex.