A rhombus is a four-sided shape where every side is the same length — think of a "squashed square." This calculator finds its area, perimeter, and diagonals from whichever pair of measurements you already have, whether that's the diagonals, a side with its height, or a side with an angle.
How the Rhombus Calculator works
All three area formulas describe the same shape from different angles: A = ½·d₁·d₂ uses the diagonals directly, A = base·height treats the rhombus like a slanted parallelogram, and A = s²·sinθ uses the side length and an interior angle. Because a rhombus's diagonals always bisect each other at a right angle, knowing any two of {side, height, angle, d₁, d₂} is enough to derive all the others — that's why this calculator can compute the full set of measurements no matter which input mode you pick.
Inputs and what they mean
In Side + Height mode, the height can never be larger than the side — if it were, the shape wouldn't close up into a rhombus. In Diagonals mode, both diagonals must be positive; the calculator derives the side automatically using the Pythagorean relationship between the half-diagonals. In Side + Angle mode, the angle is any one of the four interior angles, entered in degrees between 0° and 180° — since opposite angles are equal, it doesn't matter which one you measure.
Limits and edge cases
When the interior angle is exactly 90°, the rhombus becomes a square and both diagonals come out equal — try the Side + Height example with height equal to the side to see this. This calculator assumes a simple (non-self-intersecting) rhombus with positive side lengths; entering a height greater than the side, or an angle of 0° or 180°, describes a degenerate shape with no area, so those inputs are rejected.