About

Miscalculating volume in cubic feet leads to material shortages on job sites, overcharges on freight shipments, and incorrect HVAC sizing. A rectangular space requires L × W × H in consistent linear units before conversion to ft³. This tool handles five solid geometries and nine output unit conversions. It accepts input in inches, feet, yards, centimeters, or meters and normalizes internally to feet before applying the relevant volume formula. Results are exact to four decimal places.

One cubic foot equals exactly 1728 in³, 28316.846592 cm³, or 7.48052 US gal. The tool approximates volume for ideal geometric solids. Real-world objects with irregular surfaces, draft angles, or internal voids require volumetric displacement measurement instead. Pro tip: when ordering concrete, add 10% waste factor to the calculated cubic footage.

Formulas

Rectangular / box volume:

V = L × W × H

Cylinder volume:

V = π × r² × h

Sphere volume:

V = 43 × π × r³

Cone volume:

V = 13 × π × r² × h

Triangular prism volume:

V = 12 × b × h_tri × l

Where L = length, W = width, H = height, r = radius, h = height of solid, b = base of triangle, h_tri = triangle height, l = prism length. All dimensions must be in the same linear unit before conversion to ft. The volume in native cubic units is then divided or multiplied by the appropriate factor to yield ft³. For inches: divide by 1728. For centimeters: divide by 28316.846592. For meters: multiply by 35.314667. For yards: multiply by 27.

Reference Data

Unit	Equivalent in ft³	Common Use
1 in³	0.000578704	Small parts, jewelry
1 ft³	1.000000	Shipping, storage
1 yd³	27.000000	Concrete, gravel, mulch
1 cm³	0.0000353147	Medical, laboratory
1 m³	35.314667	International shipping
1 liter	0.0353147	Liquids, beverages
1 US gallon	0.133681	Fuel, paint, water tanks
1 Imperial gallon	0.160544	UK fluid measurement
1 US dry gallon	0.155556	Grain, dry goods
1 US bushel	1.244456	Agriculture, produce
1 US liquid quart	0.0334201	Cooking, engine oil
1 board foot	0.083333	Lumber pricing
1 cord (firewood)	128.000000	Firewood sales
1 barrel (oil)	5.614583	Petroleum industry
1 acre-foot	43560.000	Water resource management
1 CCF	100.000000	Natural gas billing

Frequently Asked Questions

Divide the cubic inches value by 1728. One foot equals 12 inches, so one cubic foot equals 12 × 12 × 12 = 1728 cubic inches. For example, 3456 in³ ÷ 1728 = 2.0 ft³.

The standard volume formula for a cylinder is V = π × r² × h. If you only know the diameter, divide it by 2 to get the radius before entering it. This tool expects radius input for cylindrical and spherical shapes. Entering diameter directly will yield a result 4× too large.

Measure the slab length, width, and thickness in the same unit. Use the rectangular shape mode. For a 10 ft × 12 ft × 0.333 ft (4-inch) slab, the result is 39.96 ft³. Concrete is sold by the cubic yard (1 yd³ = 27 ft³), so divide by 27 to get approximately 1.48 yd³. Add 10% waste factor for a practical order of 1.63 yd³.

For solids, no. For gases, yes. Gas volume changes with temperature and pressure per the ideal gas law (PV = nRT). This calculator computes geometric volume of a fixed shape. If you are measuring gas storage capacity, the actual gas quantity at different conditions requires separate PVT correction calculations.

One US gallon equals 0.133681 ft³ (231 in³). One Imperial gallon equals 0.160544 ft³ (277.42 in³). The Imperial gallon is approximately 20% larger. Confusing the two in tank sizing or fluid shipping calculations produces significant errors at scale.

Not directly. This tool handles five standard geometric solids. For irregular shapes, decompose the object into simpler sub-shapes (rectangles, cylinders, etc.), calculate each sub-volume separately, then sum them. Alternatively, use the water displacement method: submerge the object and measure the displaced water volume.