Parallelogram Calculator
Enter any valid combination of parallelogram dimensions to instantly get area, perimeter, height, interior angles, and diagonals. Designed to be more flexible than classic single-form calculators.
parallel sides
perpendicular to base
leave blank if unknown
included angle
Area from diagonals: A = (d1 × d2 × sin φ)/2
Parallelogram formulas used
Area (base & height): \( A = b \cdot h \)
Area (sides & angle): \( A = a \cdot b \cdot \sin(\theta) \)
Perimeter: \( P = 2(a + b) \)
Height (relative to a): \( h = b \cdot \sin(\theta) \)
Diagonals: \( d_1 = \sqrt{a^2 + b^2 - 2ab\cos(\theta)} \), \( d_2 = \sqrt{a^2 + b^2 + 2ab\cos(\theta)} \)
Area (diagonals & angle φ): \( A = \frac{d_1 d_2 \sin(\varphi)}{2} \)
FAQs
Can I use any units?
Yes. As long as you use the same unit for all inputs, the output area will be in the corresponding squared unit (cm → cm², ft → ft², etc.).
Why is the perimeter missing in the diagonals tab?
To compute the perimeter we need at least one side length. Provide side a in the field labeled “Optional side a.”
When is a parallelogram a rhombus or a rectangle?
A rhombus has all sides equal. A rectangle has 90° angles. If both are true, it’s a square. The calculator shows a note when it detects these patterns.