Irregular Area Calculator
Split an irregular space into rectangles and triangles, find the area of each section, and add the results. You can also convert a known total area between units.
Free area calculator
Irregular Shape Square Footage Calculator
Irregular Shape Square Footage Calculator: For an irregular space, break it into rectangles and triangles, calculate each section, and add the results.
Known Area
Room Dimensions
Multiple Rooms
Room (Feet + Inches)
ft
in
ft
in
Rectangle (Feet + Inches)
ft
in
ft
in
Wall & Window Dimensions
Cathedral Wall Dimensions
Square Dimensions
Rectangle Dimensions
Rectangle Border
Circle Dimensions
Circle Border (Annulus)
Annulus Dimensions
Triangle (3 Sides)
Triangle (Base & Height)
Trapezoid
Regular Polygon
Area + Depth (Volume)
Material Waste FactorOPTIONAL
%
Estimate Material CostOPTIONAL
Calculation Results
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How It Works
1
Select Shape
Choose the shape that matches your space.
2
Enter Dimensions
Enter measurements in any unit. Add quantity, waste factor, and material price if you need them.
3
Get Results
See area in ft², in², yd², m², and acres, plus a cost estimate when you enter a price.
Frequently Asked Questions
How do I find the square footage of an irregular shape?
Break the shape into rectangles, triangles, circles, or trapezoids you can measure. Calculate each section, then add the areas for the total square footage.
What methods work for measuring irregular areas?
Common options: split into regular shapes and add areas; overlay a grid and count full and partial squares; or use a planimeter or GPS tool outdoors. Splitting into shapes is the most practical for home projects.
How do I estimate area for a curved space?
Approximate curves with straight segments or use circle and semicircle math. A bay window might be a half-circle plus a rectangle. Curved garden borders can be a string of small trapezoids along the curve.
Can I break an irregular shape into regular shapes?
Yes, and that is usually the best approach. Draw lines to split the space into rectangles, triangles, and other simple shapes. Measure each, calculate with the matching formula here, and sum the results.
Tips for measuring irregularly shaped rooms?
Sketch the room first and label measurements. Measure from fixed points like corners. A laser meter saves time. Re-measure anything that looks off. Add 5 to 10% extra for materials.