Cubic Feet Calculator

Background.

A cubic feet calculator answers a question that shows up across construction, shipping, and home projects alike: how much volume does this space or object hold? Concrete is ordered by the cubic yard. Mulch, topsoil, and gravel are sold by the cubic foot or cubic yard. Shipping and storage quotes are frequently based on cubic feet or cubic meters. A fish tank, a raised garden bed, or a storage bin all need volume, not just floor area, to be sized correctly. This calculator takes length, width, and height in any of four common units and returns volume in cubic feet, cubic meters, and cubic yards together, so the result is usable no matter which unit a supplier, shipping quote, or spec sheet happens to use.

The reason a unit selector matters here is that construction and shipping measurements arrive in inconsistent units even within a single project. A lumber yard quotes board dimensions in inches. A room's dimensions are measured in feet. An imported product spec sheet lists dimensions in centimeters or meters. Converting all of these by hand before multiplying them together is a common source of order-of-magnitude errors — forgetting to convert inches to feet before multiplying three dimensions together produces an answer that is off by a factor of 1,728 (12 cubed), which is easy to miss until a supplier questions an order that is either absurdly large or absurdly small. This calculator removes that risk by handling the unit conversion internally: pick the unit your measurements are already in, enter the three dimensions as measured, and the calculator converts everything to a common base before multiplying.

The conversion itself uses the exact factors defined by the International System of Units: one inch equals exactly 0.0254 meters, one foot equals exactly 0.3048 meters, and one centimeter equals exactly 0.01 meters — all exact by international definition, not rounded approximations. From there, one cubic foot equals exactly 0.3048 cubed, or 0.028316846592, cubic meters, and one cubic yard equals exactly 27 cubic feet, since a yard is exactly 3 feet on each side and 3 cubed is 27. These exact relationships mean the calculator's cubic feet, cubic meters, and cubic yards outputs are always mutually consistent — converting the same physical volume through inches, feet, centimeters, or meters produces the same three answers every time, which is a useful way to sanity-check a measurement taken in an unfamiliar unit.

All three volume units are always returned together, regardless of which input unit was selected, because different downstream uses call for different units: a concrete order is typically placed in cubic yards, a shipping container's capacity is often quoted in cubic meters, and many U.S. retail bagged materials (mulch, soil, gravel) are sold by the cubic foot. Rather than forcing a second calculation or a manual conversion after the fact, this calculator returns the figure every common use case needs from a single set of inputs.

What is cubic feet calculator?

Volume, in this calculator's context, is the three-dimensional space enclosed by a rectangular box shape — length times width times height. It differs from area (a two-dimensional square-footage measurement) by adding a third dimension, and it is the correct measurement for anything sold, shipped, or poured by capacity rather than by surface: concrete, mulch, soil, gravel, water, storage volume, and shipping cargo space.

The calculator supports four input units — inches, feet, centimeters, and meters — applied uniformly to length, width, and height, and it converts internally to a common metric base before computing volume, so mixing measurement systems on a single spec sheet is not a problem as long as all three dimensions are entered in the same selected unit. The three outputs — cubic feet, cubic meters, and cubic yards — are the units most commonly required by U.S. construction suppliers, international shipping and storage quotes, and landscaping material retailers, respectively.

This calculator assumes a simple rectangular (box-shaped) volume. It is not appropriate for cylindrical, spherical, or irregularly shaped volumes — a cylinder volume calculator or sphere volume calculator should be used for those shapes instead.

How to use this calculator.

1. 01Select the unit your length, width, and height measurements are in.
2. 02Enter length, width, and height using that unit.
3. 03Read volume in cubic feet, cubic meters, and cubic yards — all three are always shown together.
4. 04If your supplier or shipping quote uses a different unit than you measured in, just change the length/width/height unit selector rather than converting by hand.

The formula.

The calculator first converts length, width, and height to meters using the exact SI factors: 1 inch = 0.0254 meters, 1 foot = 0.3048 meters, 1 centimeter = 0.01 meters, and 1 meter = 1 meter (no conversion needed). All three dimensions use the same selected unit, so this step puts every dimension on a common base before any multiplication happens.

Volume in cubic meters is then simply the product of the three converted dimensions: length times width times height. From that cubic-meter figure, cubic feet is computed by dividing by 0.028316846592 — the exact volume of one cubic foot in cubic meters, since 0.3048 cubed equals that value precisely. Cubic yards is computed by dividing the cubic-feet figure by 27, since one cubic yard is exactly 3 feet cubed, or 27 cubic feet.

Because every unit routes through the same meters-based conversion before multiplication, entering the same physical box in any of the four supported units — say, 10 by 8 by 6 feet, or the equivalent 120 by 96 by 72 inches — produces exactly the same volume in all three output units. This cross-unit consistency is a useful way to double-check a measurement: if converting a dimension from feet to inches and re-entering it changes the answer, one of the two measurements was entered incorrectly.

A worked example.

Frequently asked questions.

References& sources.

1. [1]National Institute of Standards and Technology. NIST Special Publication 811, Guide for the Use of the International System of Units (SI), Appendix B: Conversion Factors.
2. [2]Bureau International des Poids et Mesures (2019). The International System of Units (SI Brochure), 9th edition.
3. [3]National Institute of Standards and Technology (2026). NIST Handbook 133, Appendix E: General Tables of Units of Measurement.