Cubic Feet Calculator
Enter length, width, and height in any unit — inches, feet, yards, cm, or meters — and get the volume in cubic feet, cubic yards, cubic meters, and liters instantly.
What is a cubic feet calculator?
A cubic feet calculator finds the volume of any rectangular space or object — a room, a shipping box, a garden bed, a storage unit, or a concrete pour. You give it three measurements: length, width, and height. It multiplies them together and returns the result in cubic feet, plus several other volume units so you can use the number however you need it.
The most common use cases are moving and storage (how many cubic feet fit in a truck), home improvement (how many bags of soil or mulch to order), shipping (what size box you need), and construction (how much concrete, gravel, or fill material to buy). In every case, the math is the same — length times width times height — but the units are often different, which is where this tool saves time.
This tool sits in the CalcMora Converters section alongside other unit-based tools. If you work with numbers that need to be written out in words, the numbers to words converter handles that. For classic numeral systems, the Roman numerals converter is a quick reference. And if your project involves electrical wiring as well as space calculations, the voltage drop calculator helps you check cable sizing for any run length.
Cubic feet formula
The formula for volume of a rectangular shape is straightforward. All three measurements must be in the same unit before multiplying — or you can let this calculator handle the conversion automatically.
Volume (ft³) = Length (ft) × Width (ft) × Height (ft)
If your measurements are in other units, convert to feet first. Divide inches by 12, divide centimeters by 30.48, divide millimeters by 304.8, multiply meters by 3.28084, and multiply yards by 3.
Inches to cubic feet
ft³ = (L × W × H) ÷ 1728
There are 1728 cubic inches in one cubic foot (12 × 12 × 12).
Cubic feet to cubic yards
yd³ = ft³ ÷ 27
There are 27 cubic feet in one cubic yard (3 × 3 × 3).
Cubic feet to liters
L = ft³ × 28.3168
One cubic foot equals approximately 28.32 liters.
Cubic feet to cubic meters
m³ = ft³ × 0.0283168
One cubic foot equals approximately 0.0283 cubic meters.
How to use this cubic feet calculator
Type the length of your space or object. Choose the unit from the dropdown — feet, inches, yards, cm, or meters.
Type the width and choose its unit. You can use a different unit than the length — the calculator converts everything.
For rooms and boxes, this is the height. For soil, mulch, or concrete, this is the depth of the layer you want.
Results appear instantly in cubic feet, cubic inches, cubic yards, cubic meters, liters, and US gallons.
Hit the Copy button to grab all results as a single line of text, or share directly from the calculator.
Worked examples
Example 1: Bedroom volume
A bedroom that is 12 feet long, 10 feet wide, and 8 feet tall has a volume of 960 cubic feet. This is useful for sizing an air conditioner or air purifier, which are often rated by the cubic footage of the room they can handle.
Example 2: Shipping box in inches
A shipping box that is 18 inches long, 14 inches wide, and 10 inches tall has a volume of 1.46 cubic feet (2520 cubic inches ÷ 1728). Knowing this helps when choosing between box sizes or estimating how many boxes fit in a shipment.
Example 3: Garden bed — soil depth
A raised garden bed that is 8 feet long, 4 feet wide, and 12 inches deep needs 32 cubic feet of soil, which equals about 1.19 cubic yards. Most garden centers sell bulk soil by the cubic yard, so the conversion matters.
Example 4: Concrete slab
A concrete slab that is 20 feet long, 10 feet wide, and 4 inches thick requires 66.67 cubic feet of concrete, or about 2.47 cubic yards. Concrete is ordered by the cubic yard, so always convert before calling a supplier.
Common use cases by cubic feet
| Use case | Typical unit needed | Why cubic feet matters |
|---|---|---|
| Moving truck sizing | Cubic feet | Trucks are rated by cubic footage (e.g. 10 ft, 15 ft, 26 ft trucks) |
| Storage unit rental | Cubic feet | Units sold by cubic footage — 5×5×8, 10×10×8, etc. |
| Soil and mulch orders | Cubic yards | Divide ft³ by 27 — bulk suppliers use cubic yards |
| Concrete pours | Cubic yards | Ready-mix concrete priced per cubic yard |
| HVAC room sizing | Cubic feet | Air volume determines BTU requirements |
| Shipping and freight | Cubic feet / inches | Dimensional weight charges based on volume |
| Aquarium volume | Gallons / liters | Convert ft³ × 7.48 for US gallons |
Cubic feet calculator FAQ
How do I calculate cubic feet?
Multiply the length, width, and height of a space or object together. If all three measurements are already in feet, the result is directly in cubic feet. If your measurements are in inches, divide each one by 12 first, then multiply. If they are in centimeters, divide each by 30.48 first. This calculator handles all unit conversions automatically so you can mix units freely.
How do I convert inches to cubic feet?
Divide each measurement in inches by 12 to convert to feet, then multiply length × width × height. For example, a box that is 24 inches long, 18 inches wide, and 12 inches tall is 2 ft × 1.5 ft × 1 ft = 3 cubic feet. This calculator accepts inches directly — you do not need to convert manually.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in one cubic yard. A cubic yard is a cube that is 3 feet on each side: 3 × 3 × 3 = 27. This matters for ordering soil, mulch, gravel, and concrete, which are often sold by the cubic yard. Enter your measurements in any unit and the calculator shows the result in both cubic feet and cubic yards.
How do I calculate cubic feet for a cylinder or round space?
For a cylinder, the formula is π × radius² × height. Measure the diameter of the circular opening, divide by 2 to get the radius, then use the formula. This calculator handles rectangular shapes (boxes and rooms). For cylinders such as tanks and pipes, the pipe volume calculator is a better fit.
How do I calculate how much soil or mulch I need in cubic feet?
Measure the length and width of the area in feet, then decide how deep you want the material. Convert the depth to feet (for example, 3 inches = 0.25 feet). Multiply length × width × depth to get cubic feet. Divide by 27 to get cubic yards if your supplier uses that unit. This calculator shows both automatically.
What is the difference between cubic feet and square feet?
Square feet measure area — a flat, two-dimensional surface. Cubic feet measure volume — a three-dimensional space. Square feet tells you how large a floor is. Cubic feet tells you how much space is inside a room, box, or container. To go from square feet to cubic feet, multiply by the height of the space in feet.
How do I find cubic feet for shipping a package?
Measure the length, width, and height of the package in inches. Enter those three numbers into this calculator with inches selected as the unit. The result in cubic feet is the dimensional volume of your shipment. Some carriers also use dimensional weight, which divides cubic inches by a divisor (usually 139 for UPS and FedEx). This calculator gives you the raw volume to start that calculation.
This tool is for educational purposes only. Always verify important results with a qualified professional.
