Surveying & site
Triangle Area Calculator
No angles needed: three tape measurements give the exact area of any triangle - and any odd-shaped room is just triangles.
Calculator
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How it works
Heron's formula: with s = (a+b+c)/2, area = sqrt(s(s-a)(s-b)(s-c)). Split an irregular space into triangles, measure each side, and add the areas.
Frequently asked questions
How do I measure an irregular room's area?
Divide it into triangles with string or chalk lines, measure all three sides of each, compute each area here and sum them. Or scan it with RoomPlot and read the area instantly.
Why does the tool say my sides are invalid?
The two shorter sides must add up to more than the longest one - otherwise they physically cannot meet to form a triangle. Re-check the longest measurement.