Room Area Calculator
Calculate rectangular, triangular or elliptical room area.
Loading calculator…
What this tool does
Calculate rectangular, triangular or elliptical room area. Ellipse dimensions are full axes; triangle width is perpendicular height.
How to use the Room Area Calculator
- Enter or select length in ft.
- Enter or select width in ft.
- Enter or select shape.
- Read the calculated result; change any measurement to compare alternatives.
Formula
rectangle=L×W; triangle=L×W/2; ellipse=π×L×W/4
- length
- Length (ft, before metric conversion)
- width
- Width (ft, before metric conversion)
- shape
- Shape
Ellipse dimensions are full axes; triangle width is perpendicular height.
Worked example
For room area calculator, the following measurements illustrate the exact method: Length: 20; Width: 10; Shape: rectangle.
Inputs
- Length20 ft
- Width10 ft
- ShapeRectangle
Result
- Room area200 sq ft
Results explained
- Room area
- Room area from the formula above, expressed in sqft before metric conversion. Ellipse dimensions are full axes; triangle width is perpendicular height.
Frequently asked questions
Use the selected shape formula; split composite rooms into non-overlapping sections.
Measure length/base and perpendicular width/height.
Use 5–10% for simple layouts and 10–15% for diagonal cuts or complicated outlines; the allowance is editable.
Split the outline into rectangles or triangles and calculate each section separately. Do not count overlapping sections twice.
This is a purchasing estimate, not a structural design. Confirm measurements and local requirements before buying or building.