Parallelogram Calculator

A parallelogram is a four-sided polygon with two pairs of parallel sides. Opposite sides are equal in length and opposite angles are equal. Rectangles, rhombuses, and squares are all special cases of parallelograms.

Multiply the base by the perpendicular height: A = base × height. The height is not the slant side; it is the perpendicular distance from the base to the opposite parallel side. For a parallelogram with base 10 and height 6, the area is 60 square units.

Add up all four sides: P = 2 × (base + slant side), since opposite sides are equal. For base 10 and slant side 7, the perimeter is 2 × 17 = 34 units.

The slant side is the actual length of the non-base side, drawn at whatever angle the parallelogram leans. The height is shorter than the slant side (or equal when it is a rectangle) and is measured perpendicular to the base. The two are linked by sin(angle) = height ÷ slant side.

Yes. A rectangle is a parallelogram with all four angles equal to 90°. When the height equals the slant side, the parallelogram is a rectangle. Squares add the further constraint that the base equals the slant side.

The interior angle at the base is found from sin(angle) = height ÷ slant side. If you provide height and slant side, the calculator returns the angle in degrees. The opposite angle is the same; the adjacent angles total 180°.