The Cubic Feet Calculator converts length, width and height into volume in cubic feet, the base unit for moving estimates, storage sizing, HVAC loads and material orders measured as a solid rather than a flat area. Rooms, boxes, cylinders, cones and area-times-depth all route through the same engine. Results also show cubic yards, cubic metres, litres and US gallons alongside the primary cubic-foot figure.
Calculate cubic feet from length, width and height
A cubic foot is a cube one foot on every edge, and any rectangular volume is the product of its three dimensions once each one is expressed in feet. A room, a packing box and a storage unit all use the identical multiplication; only the labels on the three inputs change.
Volume (ft³) = Length (ft) × Width (ft) × Height (ft)A moving box, a garden bed dug to a depth, and a water tank all reduce to length times width times height, or to area times depth when two of the three dimensions have already been combined into a single square-footage figure. The calculator accepts either path: three separate dimensions, or one area field plus a depth.
Convert measurements before multiplying
Cubic feet only comes out correctly when every input dimension is in feet before the multiplication happens, and the most common error on this calculation is multiplying a length in feet by a depth still in inches. Divide inches by 12 first; divide centimetres by 30.48, or convert to metres and multiply by 0.3048 per metre of length.
A packing crate measured at 36 inches long, 24 inches wide and 18 inches tall converts to 3 ft, 2 ft and 1.5 ft before multiplying: 3 × 2 × 1.5 = 9 ft³. Skipping the conversion and multiplying the raw inch values would return 15,552, a number in cubic inches rather than cubic feet, off by a factor of 1,728. The calculator's unit selector on each dimension field removes this step entirely; enter inches and select "in", and the conversion happens before the multiplication runs.
Apply the cubic feet formula
Every solid shape resolves to length times width times height, or an equivalent formula built from a radius and a height, and there are 1,728 cubic inches in every cubic foot because 12 × 12 × 12 = 1,728. That figure is the one to remember when a dimension arrives in inches and the result needs to land in feet.
L × W × H = Volume (ft³)
12 in × 12 in × 12 in = 1,728 in³ = 1 ft³A cube with a 2 ft side has a volume of 2 × 2 × 2 = 8 ft³. A box quoted in inches, at 24 in × 18 in × 12 in, has a volume of 24 × 18 × 12 = 5,184 in³, which divided by 1,728 gives exactly 3 ft³. Both paths, converting the dimensions first or converting the final cubic-inch total, arrive at the same answer; converting the dimensions first is less error-prone because the running total stays in a unit that is easy to sanity-check.
Estimate a moving load from box counts
Moving companies quote by truck volume, and a household load is the sum of every box's individual volume plus furniture measured the same way. The calculator's box accumulator adds standard sizes by count rather than requiring each box to be measured separately.
Three standard sizes cover most household moves: a small box at 1.33 ft³, a medium box at 3.0 ft³, and a large box at 4.5 ft³. A move with 10 small boxes, 8 medium boxes and 5 large boxes totals:
1. Small boxes. 10 × 1.33 ft³ = 13.3 ft³
2. Medium boxes. 8 × 3.0 ft³ = 24.0 ft³
3. Large boxes. 5 × 4.5 ft³ = 22.5 ft³
4. Add the three totals. 13.3 + 24.0 + 22.5 = 59.8 ft³
That figure, 59.8 ft³, is the box volume alone; furniture and appliances are entered as separate rectangular or cylindrical items and added to the same running total. Movers typically build in 15 to 20 percent air space on top of the summed volume, since boxes rarely stack with zero gaps, so a truck sized for exactly 59.8 ft³ runs tight.
Size a storage unit from cubic feet
A storage unit's advertised size is its floor plan, not its usable volume, and packing efficiency, not raw capacity, determines what actually fits. An 8 ft ceiling is standard, and boxes, furniture and irregular gaps mean a unit is rarely packed past about 60 percent of its raw volume.
| Unit | Floor plan | Raw volume at 8 ft | Usable at 60% packing |
|---|---|---|---|
| 5 × 5 | 25 ft² | 200 ft³ | 120 ft³ |
| 5 × 10 | 50 ft² | 400 ft³ | 240 ft³ |
| 10 × 10 | 100 ft² | 800 ft³ | 480 ft³ |
| 10 × 15 | 150 ft² | 1,200 ft³ | 720 ft³ |
| 10 × 20 | 200 ft² | 1,600 ft³ | 960 ft³ |
The 59.8 ft³ box load from the moving example above needs a raw capacity of 59.8 ÷ 0.6 = 99.7 ft³ once packing inefficiency is accounted for, which the 200 ft³ raw volume of a 5×5 unit clears easily at 120 ft³ usable. Furniture that will not stack, such as a mattress or a couch, eats into that usable figure faster than boxes do, so a load with bulky furniture should size up from whatever the box count alone suggests.
Calculate cubic feet for landscaping material
Landscaping material is bought by volume, and a small bed measured in cubic feet often does not need the cubic-yard conversion that a full delivery order does. Multiply the bed's area by its depth in feet to get cubic feet directly, then compare that figure to the coverage printed on a bagged product.
A container garden bed measuring 4 ft by 3 ft, filled 3 inches deep, needs 4 × 3 × (3 ÷ 12) = 12 × 0.25 = 3 ft³ of material. A bagged soil or mulch product sold at 2 ft³ per bag covers that bed in one and a half bags, rounding up to two. Bulk delivery is rarely worth arranging below a few cubic yards; small beds like this one are the case where bags and cubic feet are the more practical unit than a bulk cubic-yard order.
Convert cubic feet to other volume units
Cubic feet converts to every other common volume unit through a fixed factor, and the calculator displays several at once so a single result serves both a US delivery quote and a metric spec sheet without a second calculation.
| Convert from ft³ | Factor | Example |
|---|---|---|
| To cubic yards | Divide by 27 | 81 ft³ ÷ 27 = 3 yd³ |
| To cubic metres | Multiply by 0.02832 | 100 ft³ × 0.02832 = 2.83 m³ |
| To US gallons | Multiply by 7.48 | 10 ft³ × 7.48 = 74.8 gal |
| To litres | Multiply by 28.32 | 5 ft³ × 28.32 = 141.6 L |
| To US quarts | Multiply by 29.92 | 1 ft³ × 29.92 = 29.92 qt |
Twenty-seven cubic feet make exactly one cubic yard, since a yard measures three feet on a side and 3 × 3 × 3 = 27. That conversion belongs to bulk material ordering rather than boxes and rooms, and the Cubic Yards Calculator carries the full explanation, coverage tables and bag counts built on top of it.
Calculate volume of non-rectangular shapes
Not every solid is a box, and the calculator covers the common curved and angled forms alongside the rectangular ones. A cylinder is the circle's area times its height; a cone and a pyramid both carry a one-third factor because they taper to a point; a sphere depends on the cube of its radius.
Cylinder = π × (Diameter ÷ 2)² × Height
Cone = ⅓ × π × (Diameter ÷ 2)² × Height
Sphere = (4 ÷ 3) × π × (Diameter ÷ 2)³
Pyramid = ⅓ × Length × Width × Height
Triangular prism = ½ × Base × Height × LengthA cylindrical rain barrel 2 ft across and 3 ft tall holds π × 1² × 3 = 9.42 ft³. A conical hopper with the same diameter and height holds a third of that, 3.14 ft³, because the taper removes two-thirds of the equivalent cylinder's volume. Capsule and frustum shapes, common in tanks, combine a cylinder with one or two curved end caps and are covered on the Tank Volume Calculator, which carries the fill-level arithmetic those shapes need.
Frequently asked questions
How many cubic feet are in a cubic yard?
Twenty-seven. A cubic yard is a cube 3 ft on every side, and 3 × 3 × 3 = 27 ft³. This is the conversion bulk material suppliers use to translate a delivered cubic-yard order into the cubic-foot volume a bed or trench actually holds.
How do I convert inches to cubic feet?
Convert each dimension from inches to feet by dividing by 12, then multiply the three feet-based dimensions together. A box measuring 24 in by 18 in by 12 in becomes 2 ft by 1.5 ft by 1 ft, giving 2 × 1.5 × 1 = 3 ft³.
How many cubic feet is a 5x5 storage unit?
At a standard 8 ft ceiling, a 5×5 storage unit has 200 ft³ of raw volume. Usable capacity is lower once packing inefficiency is factored in, typically around 120 ft³ at 60 percent packing, since boxes and furniture do not stack with zero gaps.
How much does one cubic foot of water weigh?
About 62.4 lb at typical temperatures, or roughly 28.3 kg. This figure is separate from the volume conversions on this page and is used mainly for tank load calculations, where the weight a structure supports matters as much as the gallons it holds.
How do I calculate cubic feet for a moving estimate?
Sum the cubic footage of every box and item of furniture. Standard boxes run about 1.33 ft³ small, 3.0 ft³ medium and 4.5 ft³ large; a load of 10 small, 8 medium and 5 large boxes totals 59.8 ft³ before furniture and before the air-space allowance movers typically add on top.
What is 1,728 cubic inches equal to?
Exactly one cubic foot. The figure comes from 12 × 12 × 12, since there are 12 inches in a foot and a cubic foot has that dimension on all three sides. Dividing any cubic-inch total by 1,728 converts it to cubic feet.
How do I find the cubic feet of a cylinder?
Multiply pi by the square of the radius, then by the height: π × r² × h. A cylinder 2 ft in diameter (a 1 ft radius) and 3 ft tall holds π × 1² × 3, or about 9.42 ft³.
How many cubic feet are in a gallon?
One US gallon is about 0.1337 ft³, so one cubic foot holds about 7.48 US gallons. A 50-gallon tank has a volume of roughly 50 × 0.1337 = 6.68 ft³.
How do I calculate cubic feet for an irregularly shaped room?
Split the room into rectangular or cylindrical sections the same way an irregular floor plan is split for square footage, find the volume of each section separately using its own height, and add the sections together. A stepped ceiling or a bay window is measured as its own smaller box rather than forcing one uniform height across the whole room.
Does cubic feet measure weight or volume?
Volume only. Cubic feet describes the space a solid or a container occupies, not how much it weighs. Two materials filling the same 10 ft³ space, such as insulation and gravel, can differ in weight by a factor of a hundred or more, so a weight figure always needs a separate density applied on top of the cubic-foot volume.
Summary
The Cubic Feet Calculator turns length, width and height into volume using a single multiplication once every dimension is converted to feet, with 1,728 cubic inches making one cubic foot and 27 cubic feet making one cubic yard. Box and room volumes, moving loads, storage-unit sizing and non-rectangular shapes such as cylinders and cones all run through the same engine.
Convert every input dimension before multiplying, size storage around usable rather than raw volume, and hand off to the Cubic Yards Calculator once a result needs to become a bulk material order.