Concrete Surface Area Calculator
Find the surface area of a slab, driveway, patio, or foundation. For concrete volume, add a separate depth calculation.
Free area calculator
Concrete Square Footage Calculator
Concrete Square Footage Calculator: Calculate surface area for concrete slabs, driveways, patios, and foundations. Cubic yards need a separate
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 calculate square footage for a concrete project?
Measure length and width of the pour area and multiply for surface area in square feet. For how much concrete to order, you also need slab thickness (depth).
How do I convert square footage to cubic yards of concrete?
Multiply area (sq ft) by thickness in feet, then divide by 27 for cubic yards. Example: 200 sq ft × 0.33 ft (4 inches) = 66 cu ft ÷ 27 = 2.44 cubic yards.
How much concrete do I need for a standard 4-inch slab?
For 4-inch thickness, multiply sq ft by 0.0123 to get cubic yards. Example: 500 sq ft × 0.0123 = 6.15 cubic yards. Order 5 to 10% extra for waste, spillage, and uneven subgrade.
What waste factor should I use for concrete?
Add 5 to 10%. Use 5% on flat, well-prepared ground. Use 10% or more on uneven terrain, complex forms, or lots of edges. Running short mid-pour is worse than a little extra.
How do I estimate the cost of a concrete project?
Calculate area, add waste, then enter price per square foot in Estimate Material Cost. Ready-mix concrete often runs $100 to $150 per cubic yard delivered. For cost per sq ft, divide total cost by area.