Parallelogram Area Calculator
The area of a parallelogram from its base and height.
Result
Area
40.00
How it works
The area of a parallelogram is base × height — the same formula as a rectangle, and for a good reason. Slice the slanted triangle off one end and move it to the other, and the parallelogram becomes a rectangle of identical base and height. The height is the perpendicular distance between the two parallel sides, never the length of the slanted side. That is the near-universal mistake: a parallelogram with a base of 10 and a slanted side of 6 has an area of 60 only if that 6 is measured straight across at a right angle. Because the area ignores how far the shape leans, a whole family of parallelograms of increasing slant share the same area — as long as base and height are unchanged. Squares and rectangles are simply the special cases where the lean is zero.
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Frequently asked questions
Which height do I use?
The perpendicular distance between the base and the opposite side, not the slanted edge.
Is it like a rectangle?
Yes — a parallelogram has the same area as a rectangle of equal base and height.
Is a parallelogram just a slanted rectangle?
For area purposes, yes: both use base × height. Rearranging the triangle at one end turns a parallelogram into a rectangle of the same base and height, which is why the formula is identical.
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