# Parallelogram Calculator

URL: https://speedycalculator.com/calculators/math/parallelogram/
Last updated: 2026-10-25

> The parallelogram calculator finds area, perimeter and diagonals from two adjacent sides and the angle between them.

## Inputs

- Side a (m, cm, mm, km, in, ft, yd, mi)
- Side b (m, cm, mm, km, in, ft, yd, mi)
- Angle between sides (°)

## Results

- Area
- Perimeter
- Long diagonal
- Short diagonal

## Formula

```
Area = a × b × sin(θ)
Diagonals: √(a² + b² ± 2ab cos θ)
```

## Explanation

A parallelogram has two pairs of parallel sides. Rectangles and rhombuses are special cases.

### How to use the Parallelogram Calculator

- **Side a**
- **Side b**
- **Angle between sides**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

The area is base times height, where height = b × sin θ. The diagonals follow from the law of cosines.

### Inputs explained

FieldWhat to enterSide aUnits: m, cm, mm, km, in, ft …Side bUnits: m, cm, mm, km, in, ft …Angle between sidesIn °

### What each result means

- **Area** = [Side a]×[Side b]×sin(rad([Angle between sides]))
- **Perimeter** = 2×([Side a] + [Side b])
- **Long diagonal** = sqrt([Side a]^2 + [Side b]^2 + 2×[Side a]×[Side b]×abs(cos(rad([Angle between sides]))))
- **Short diagonal** = sqrt([Side a]^2 + [Side b]^2 - 2×[Side a]×[Side b]×abs(cos(rad([Angle between sides]))))

### Example values

How the main result changes when **Side a** changes and everything else stays at the example values above:

Side a (m)Area (m²)525.987.538.971051.9612.564.951577.9420103.92

## Worked example

Inputs — Side a: 10 m; Side b: 6 m; Angle between sides: 60 °.

Results — **Area = 51.96 m²**; Perimeter = 32 m; Long diagonal = 14 m; Short diagonal = 8.72 m.

## FAQ

**What if the angle is 90°?**
The parallelogram is a rectangle.

**Do opposite angles match?**
Yes, and adjacent angles add to 180°.

**What formula does the Parallelogram Calculator use?**
Area = a × b × sin(θ).