Everyday Life
Concrete & Mulch Volume Calculator
Calculate the volume of concrete, soil, or mulch needed for slabs, walls, and circular holes.
Inputs
Results
1.23 Cubic Yards
Volume Required
Volume in Cubic Feet
0.00 cu ft
Volume in Cubic Meters
0.00 m³
Estimated 80-lb Concrete Bags
0 Bags
Estimated 60-lb Concrete Bags
0 Bags
How It Works
The calculator determines volume by multiplying slab area by thickness. For rectangular shapes: $V = L \times W \times D_{feet}$. For circular holes: $V = \pi \times r^2 \times D_{feet}$. It converts cubic feet to cubic yards by dividing by 27. It estimates bagged concrete counts using yield thresholds: $0.6\text{ cu ft}$ per 80lb bag, and $0.45\text{ cu ft}$ per 60lb bag.
Formula Used
Rectangular Volume (Cubic Feet) = Length (ft) × Width (ft) × Thickness (in) / 12
This calculates the volume of a rectangular slab. The thickness is divided by 12 to convert inches to feet, ensuring all dimensions are in the same units.
Circular Volume (Cubic Feet) = π × Radius (ft)^2 × Thickness (in) / 12
This calculates the volume of a cylindrical hole, multiplying the base area (pi times radius squared) by the thickness in feet.
Volume (Cubic Yards) = Volume (Cubic Feet) / 27
To convert cubic feet to cubic yards (the standard unit for bulk concrete sales), the total cubic volume is divided by 27.
Worked Example
Here is a step-by-step example of how these values are calculated:
Shape
Rectangular Slab
Length
10 ft
Width
10 ft
Depth
4 inches
Result: Volume: `33.33 cubic feet` (`1.23 cubic yards`). Requires `56` bags (80-lb concrete).
Frequently Asked Questions
How deep should a concrete patio or driveway be?
Standard concrete patios, sidewalks, and residential footings are typically poured to a depth of 4 inches. Driveways carrying vehicles should be poured to a thickness of 5 or 6 inches.
How much extra concrete should I order?
It is standard practice to add a 10% spill/waste margin to account for grading variations, form bowing, and general handling waste.