Cubic Feet Calculator Volume & Weight Planner
Reviewed by Construction Estimators
Last updated June 2026
Estimating Tip: When calculating materials like soil, concrete, or gravel, always buy 10% to 15% extra. Physical material compacts during installation, and some volume is lost due to spills or uneven excavation beds.
Calculate total three-dimensional volume in cubic feet for rectangular, cylindrical, or spherical shapes. Instantly convert to cubic yards, gallons, or liters.
Quick Answer: What is a Cubic Foot?
A cubic foot (abbreviated as cu ft or ft³) is a standard imperial unit of volume. It represents the space occupied by a cube measuring 1 foot on all three sides.
Formula: Volume = Length (ft) × Width (ft) × Depth (ft). For cylindrical columns, use the equation: pi × Radius² × Height.
Understanding Cubic Feet Volume (ft³)
A cubic foot is a measure of volume. It represents the space contained within a three-dimensional boundary. This unit is heavily utilized across North America for buying landscaping materials (mulch, topsoil), purchasing construction goods (concrete, sand), measuring appliance capacities (refrigerators, freezers), and calculating shipping cargo.
While linear feet measure length, and square feet measure two-dimensional surface area, cubic feet allow you to quantify height, width, and depth in a single measurement. Knowing how to calculate cubic feet prevents overpaying for supply orders or underestimating shipping costs.
Cubic Feet Formulas for Common Geometric Shapes
Depending on the shape of the space or object you are measuring, you will use a different mathematical formula. Ensure all starting dimensions are converted to feet before using these equations:
1. Rectangular Box / Area
Used for garden beds, square rooms, storage boxes, and footings:
Cubic Feet = Length (ft) × Width (ft) × Depth (ft)
2. Cylinder / Round Column / Pipe
Used for cylindrical sonotube footings, compost bins, and drainage pipes:
Cubic Feet = pi × Radius² (ft) × Height (ft)
Note: Radius is half of the total diameter.
3. Sphere / Globe
Used for spherical tanks, play balls, or landscape decorative globes:
Cubic Feet = (4 / 3) × pi × Radius³ (ft)
Volumetric Conversion Rates
Often, suppliers or shippers list volumes in other units, such as cubic yards (for gravel/mulch) or gallons/liters (for liquids). Here is how you can easily map cubic feet to alternative metrics:
- To Cubic Yards: Divide cubic feet by 27. (e.g. 108 CFT / 27 = 4 Cubic Yards).
- To Cubic Inches: Multiply cubic feet by 1,728. (e.g. 1 CFT = 1,728 cubic inches).
- To US Gallons: Multiply cubic feet by 7.48052. (e.g. 10 CFT = 74.8 gallons of water).
- To Liters: Multiply cubic feet by 28.3168. (e.g. 2 CFT = 56.6 liters).
Material Densities & Weight Estimates
Knowing the volume in cubic feet is critical, and knowing the weight is required for planning logistics. The table below represents dry density weights for common construction and yard materials:
| Material Type | Weight per Cubic Foot | Weight per Cubic Yard |
|---|---|---|
| Wet Concrete | ~150 lbs | ~4,050 lbs (2.0 Tons) |
| Gravel / Crushed Stone | ~105 lbs | ~2,835 lbs (1.4 Tons) |
| Dry Sand | ~100 lbs | ~2,700 lbs (1.35 Tons) |
| Topsoil | ~75 lbs | ~2,025 lbs (1.0 Ton) |
| Water | ~62.4 lbs | ~1,685 lbs (0.84 Tons) |
| Wood Mulch | ~20 lbs | ~540 lbs (0.27 Tons) |
Frequently Asked Questions
How do I calculate cubic feet for a rectangular area?
To calculate cubic feet, first convert all measurements (length, width, height) to feet. Then, multiply the length by the width by the height: Length (ft) × Width (ft) × Height (ft) = Cubic Feet.
How many cubic feet are in a cubic yard?
There are exactly 27 cubic feet in one cubic yard. Since a cubic yard is 3 feet long, 3 feet wide, and 3 feet deep: 3 × 3 × 3 = 27.
How do I calculate cubic feet if my measurements are in inches?
Multiply the length, width, and height in inches together to find the total cubic inches. Then, divide the result by 1,728 (since 12 × 12 × 12 = 1,728) to convert it to cubic feet.
What is the difference between square feet and cubic feet?
Square feet measure two-dimensional surface area (Length × Width), while cubic feet measure three-dimensional volume (Length × Width × Height). Cubic feet include the thickness or depth of the object.
How many gallons of liquid are in a cubic foot?
One cubic foot of volume can hold approximately 7.48 US liquid gallons. To convert cubic feet to gallons, multiply the cubic feet value by 7.48052.
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