Math
Cubic Feet Calculator
Calculate cubic feet from rooms, boxes, square feet plus depth, cylinders, logs, and concrete slabs.
Linear unit
Formula
L x W x H
Shape
Room / Box
Result
960.00 ft^3 / 27.18 m^3 / 27,184.17 L
Room / Box
cubic feet
960.00ft^3
cubic meters
27.18m^3
liters
27184.17L
US gallons
7181.30gal
Need a change for Cubic Feet Calculator?
About this calculator
Method, formulas, and limits.What this does
Calculates the volume of a space or object in cubic feet using four shape modes: rectangular room or box, square footage plus depth, cylinder or round log, and concrete slab. Converts the result to cubic meters, liters, and US gallons so you can compare across unit systems without additional math.
Who it is for
Homeowners measuring room or fridge space, contractors estimating concrete or material volume, movers calculating truck capacity, woodworkers sizing logs, and anyone who needs a quick volume check in cubic feet across imperial and metric units.
How it works
Select a shape mode and a linear unit (ft, in, m, cm). Enter the required dimensions for that mode — length, width, and height for a room; area and depth for square footage; diameter and length for a cylinder; or length, width, and depth for a slab. The calculator converts every input to feet, applies the geometric volume formula, and displays the result in four unit views.
Limitations
Assumes perfectly rectangular, cylindrical, or slab geometries. Does not account for irregular shapes, tapered columns, curved walls, rounded corners, sloping floors, void spaces, or material compression. Results are exact for the given dimensions but should be treated as estimates for real-world objects.
Key calculations
- Rectangular Volume
- Volume in cubic feet for a room, box, or slab. cuft = length(ft) × width(ft) × height(ft). Each dimension is converted to feet before multiplying.
- Square Feet Plus Depth
- Volume from an area measurement and a depth. cuft = area(sqft) × depth(ft). Depth is converted to feet from the chosen linear unit.
- Cylinder Volume
- Volume for a round log, pipe, or cylinder. cuft = π × (diameter(ft) / 2)² × length(ft). The calculator halves the diameter to get the radius, squares it, multiplies by π, then by the length.
- Unit Conversion
- After computing cubic feet, the result is converted to cubic meters (× 0.0283168), liters (× 28.3168), and US gallons (× 7.48052) for cross-unit comparison.
Reference ranges
- Small appliance or cooler
- A mini-fridge or cooler is typically 3–6 ft³. A standard dorm fridge falls around 4.5 ft³. Anything below 2 ft³ is a compact cooler or small ice chest.
- Standard refrigerator
- Full-size refrigerators range from 18 to 28 ft³. French-door models often sit at 22–26 ft³, while side-by-side units are typically 20–25 ft³.
- Concrete slab (4 in thick)
- A 10×10 ft slab at 4 in deep is roughly 33 ft³, which equals about 1.2 cubic yards of concrete. A standard parking space (9×18 ft) at 4 in is about 54 ft³.
- Round log or tree
- A log 12 in diameter and 8 ft long has about 6.3 ft³ of volume. A 24 in diameter log of the same length holds about 25 ft³. Larger timber specimens can exceed 50 ft³.
How to use it
- 1.Select a shape modeChoose between Room / Box, Square Feet + Depth, Cylinder / Round Wood, or Concrete Slab to set the input fields for your use case.
- 2.Choose a linear unitPick ft, in, m, or cm. For Square Feet + Depth mode you also pick the area unit (sq ft or sq m). All inputs are converted to feet internally.
- 3.Enter the dimensionsFill in the required fields for your mode — length, width, and height for room mode; area and depth for depth mode; diameter and length for cylinder mode; or length, width, and depth for slab mode.
- 4.Read the volume resultsThe calculator displays the volume in cubic feet, cubic meters, liters, and US gallons at once. The formula used and a mode-specific note are shown below the results.
- 5.Check the worked formulaThe formula bar shows the exact expression used for the current mode, and the note column explains the conversion or geometric rule applied.
The calculator does this automatically. When you select inches as the linear unit, it converts each inch measurement to feet by dividing by 12 before computing the volume. For a room that is 120 in × 144 in × 96 in, the equivalent in feet is 10 × 12 × 8 = 960 ft³.
Use the Square Feet + Depth mode. Enter the area in square feet and the depth in your chosen linear unit. The calculator converts the depth to feet, then multiplies: cubic feet = area(sqft) × depth(ft). This is useful when you already know the floor area of a space and just need the thickness.
Yes. Room / Box mode accepts length, width, and height in any supported unit and works perfectly for rectangular spaces. Enter the interior dimensions of your fridge, the rough dimensions of a room, or the outer size of a shipping box to get the volume in cubic feet and other units.
Yes. Cylinder / Round Wood mode uses the diameter and length to compute volume for logs, trunks, pipes, posts, and other round shapes. Measure the diameter at the midpoint, enter it along with the length, and the calculator applies the cylinder formula automatically.
The calculator displays the result in cubic feet, cubic meters, liters, and US gallons simultaneously. One cubic foot equals roughly 0.0283 cubic meters, 28.317 liters, or 7.48 US gallons. This lets you move between imperial and metric without any extra calculation.
Select the Slab mode, then enter the length, width, and depth of the slab in your preferred unit. A 10×10 ft slab that is 4 in deep gives 10 × 10 × 0.333 = 33.3 ft³. Slab mode uses the same L × W × H formula as Room mode but the result is labeled for material estimation.
No. All measurements for a single mode must use the same linear unit. If your measurements are in different units, convert them to one unit before entering them, or use the same unit for every field in the current mode. The calculator does not support mixed-unit inputs.
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