This cubic feet calculator finds the volume of any box-shaped space — a room, moving box, refrigerator, garden bed, or truck bed — from its length, width, and height. Measure in inches, feet, yards, centimeters, or meters; the calculator converts everything to feet, multiplies the three dimensions, and reports cubic feet plus cubic yards, cubic meters, liters, and US gallons.
Cubic feet (often written CFT or ft³) is the standard volume unit for appliances, freight, storage units, and landscaping material in the US. Knowing how to calculate cubic feet correctly keeps you from over-ordering soil or renting a bigger truck than you need.
How to Calculate Cubic Feet
Volume of a rectangular space is simply length × width × height, with all three dimensions in feet:
cubic feet = length (ft) × width (ft) × height (ft)
If you measured in another unit, convert to feet first:
- Inches: divide by 12 (or multiply the cubic-inch result by 1 ÷ 1,728)
- Yards: multiply by 3
- Centimeters: divide by 30.48
- Meters: divide by 0.3048 (multiply by 3.28084)
So a box measuring 24 × 18 × 12 inches is 2 × 1.5 × 1 ft = 3 cubic feet. For cylinders, use π × radius² × height instead; for irregular shapes, split the space into boxes and add the volumes.
Cubic Feet Conversions and Common Sizes
Handy equivalents when comparing quotes or spec sheets:
- 1 cubic foot = 1,728 cubic inches = 0.037 cubic yards = 0.0283 m³
- 1 cubic foot = 28.32 liters = 7.48 US gallons
- 1 cubic yard = 27 cubic feet; 1 cubic meter = 35.31 cubic feet
Typical volumes for scale: a standard refrigerator is 18–26 cu ft, a large moving box about 4.5 cu ft, a full-size pickup bed roughly 50–75 cu ft, a 10 × 10 × 8 ft storage unit 800 cu ft, and a bag of potting soil 1–2 cu ft. In India and Pakistan, timber and sand are often quoted in CFT — the same unit, calculated the same way.
Worked Example: Volume of a Raised Garden Bed
Say you are filling a raised garden bed that is 4 ft long, 3 ft wide, and 2 ft (24 inches) tall — the default values above.
Step 1 — multiply the dimensions: 4 × 3 × 2 = 24 cubic feet. Step 2 — convert to other units as needed: 24 ÷ 27 = 0.89 cubic yards, 24 × 0.0283 = 0.68 m³, or 24 × 7.48 = 179.5 US gallons.
At 1.5 cubic feet per bag, filling the bed takes 16 bags of soil — which is why most people order 1 cubic yard in bulk instead and keep the small remainder for topping up pots. If you only fill the bed 18 inches deep, the volume drops to 4 × 3 × 1.5 = 18 cubic feet.
Frequently Asked Questions
How do you calculate cubic feet?
Multiply length × width × height with all three dimensions in feet. A space 4 ft long, 3 ft wide, and 2 ft tall is 4 × 3 × 2 = 24 cubic feet. If measurements are in inches, divide each by 12 before multiplying.
How do I calculate cubic feet from inches?
Multiply the three dimensions in inches to get cubic inches, then divide by 1,728 (the number of cubic inches in a cubic foot). For example, 24 × 18 × 12 inches = 5,184 cubic inches, and 5,184 ÷ 1,728 = 3 cubic feet.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in a cubic yard, because a yard is 3 feet and 3 × 3 × 3 = 27. To convert cubic feet to cubic yards, divide by 27; to go the other way, multiply by 27.
How many gallons are in a cubic foot?
One cubic foot holds 7.48 US gallons (about 6.23 imperial gallons or 28.32 liters). To convert cubic feet to gallons, multiply by 7.48 — a 24 cubic foot tank holds roughly 180 US gallons.
What is CFT and how is it calculated?
CFT stands for cubic feet, a volume unit widely used for timber, sand, and aggregates in South Asia. It is calculated as length × width × height in feet. For timber, CFT = (length ft × breadth in × thickness in) ÷ 144 when the cross-section is measured in inches.