Volume Calculator

Whatever your project, whether you are filling a tank, ordering mulch by the yard, or figuring out how much a shipment will cost to move, you eventually run into the same question: how much space does this thing actually take up.This volume calculator works out that number for you. Pick a shape from the list, box, cylinder, sphere, cone, pyramid, and a few less common ones, enter the dimensions you already have on hand, and get an instant result along with the formula the tool used to get there. It also handles unit conversion automatically, so entering measurements in inches and getting an answer back in gallons or liters takes one click, not a separate conversion step. Choose a shape below to get started.

What Is Volume and How Do You Calculate It?

Volume is simply the amount of three-dimensional space something takes up. It is a different measurement from area, which only describes a flat, two-dimensional surface, and in most everyday situations it is treated the same as capacity, or how much a container can hold. The official SI unit for volume is the cubic meter, though in practice most people work in cubic feet, cubic yards, liters, or gallons depending on what they are measuring.

Every volume formula follows the same basic logic even though the shapes look different on paper. You are either multiplying the area of a base by a height, as with a box or cylinder, or applying a constant that accounts for how a shape tapers to a point, as with a cone or pyramid. Because volume describes three dimensions, the result is always expressed in cubic units, whether that is cubic inches, cubic centimeters, or cubic meters.

What Units Are Used to Measure Volume?

The calculator lets you work in whichever unit your dimensions are already in, then convert the result to whatever unit you actually need. The most common ones are listed below.

One detail worth flagging early: the US gallon and the Imperial gallon are not the same size, the gap is close to 20 percent, and picking the wrong one is one of the more common reasons a result looks off. We come back to the exact conversion figures further down.

How Do You Calculate Volume for Each Common Shape?

The calculator needs different inputs depending on which shape you select. A box needs length, width and height. A cylinder needs a radius and a height. A sphere just needs a radius. Once you pick a shape from the dropdown, the input fields update automatically to ask for only what that formula requires, so you are not stuck figuring out which measurement goes where.

How Do You Calculate the Volume of a Box or Cube?

For a rectangular box, volume equals length times width times height. A cube is really just a special case of a box where all three sides are equal, so its volume is simply the side length cubed.

Say you have a storage box measuring 4 feet long, 3 feet wide and 2 feet tall. Multiply those three numbers together and you get 24 cubic feet. That is the entire calculation, but the part people trip up on is unit consistency. If one side is measured in inches and another in feet, the multiplication still produces a number, it just does not mean anything useful. All three measurements need to be in the same unit before you multiply them.

How Do You Calculate the Volume of a Cylinder or Sphere?

A cylinder's volume is pi times the radius squared times the height. A sphere's volume is four thirds times pi times the radius cubed. In both cases, radius means half the diameter, and this is where a lot of manual calculations go wrong, since it is usually the diameter that gets measured first with a tape measure.

For a cylinder with a radius of 2 feet and a height of 5 feet, 3.1416 times 2 squared times 5 works out to roughly 62.8 cubic feet. For a sphere with a radius of 1.5 feet, four thirds times 3.1416 times 1.5 cubed comes to about 14.1 cubic feet.

How Do You Calculate the Volume of a Cone, Pyramid or Irregular Shape?

A cone's volume is one third times pi times the radius squared times the height, essentially a cylinder's formula scaled down because a cone tapers to a point instead of keeping a constant cross-section. A pyramid follows the same logic: one third times the base area times the height.

For shapes that do not match any standard formula, the usual approach is to break the object down into simpler pieces you already know how to calculate, work out each piece separately, then add the results together. An L-shaped room, for instance, can be split into two rectangles. If the object is something you can physically submerge in water, there is also a more direct option: lower it into a container filled to a marked line, note how much the water level rises, and that difference in volume is the object's volume. It is a slower method, but it works even when you cannot get a clean set of dimensions.

How Do You Calculate the Volume of a Triangular Prism, Capsule or Other Specialty Shape?

Beyond the shapes above, a handful of less common ones come up often enough to be worth mentioning. A triangular prism's volume is the base times the height of the triangle, times the length of the prism, divided by two. Capsules, spherical caps, conical frustums, ellipsoids and tubes each have their own formula built around combining or trimming the basic shapes covered earlier. A capsule, for example, is really just a cylinder with a half sphere capping each end. Rather than walk through every one of these here, each has its own dedicated calculator. Try the triangular prism volume calculator, capsule volume calculator, or ellipsoid volume calculator if your shape falls into one of these categories.

How Do You Use the Volume Calculator Tool?

Using the tool comes down to three steps. First, pick the shape you are working with from the dropdown menu. Second, enter the dimensions the tool asks for, whatever labels appear once you have chosen a shape. Third, read the result, which comes with the formula it used so you can see exactly how the number was reached rather than just trusting a black box. That last part matters more than it sounds. If you are about to order concrete or pay for freight based on this number, being able to see the working lets you catch a mistyped digit before it costs you money.

What Inputs Does the Calculator Need and How Do You Switch Units?

Boxes and prisms ask for linear dimensions: length, width and height. Round shapes ask for a radius or diameter plus a height where relevant. You can switch between metric and imperial units at any point, and the tool converts your entries automatically, so there is no need to do that math by hand before typing anything in. The one thing to watch is entering all your dimensions in the same unit before you calculate, since mixing centimeters with inches is the single most common cause of a wrong result.

What Common Mistakes Affect Volume Calculations?

A few errors show up again and again, based on the kinds of questions people ask once they get a number that does not look right. Mixing units within a single calculation is the most frequent one. Confusing a US gallon with an Imperial gallon is close behind. And a surprising number of people assume that converting a volume from gallons to liters also tells them something about weight, which it does not.

Why Does Mixing Units or Confusing Volume with Weight Cause Errors?

Every dimension you feed into a volume formula has to share the same unit, or the multiplication produces a number with no real meaning. Say you measure a box as 24 inches long, 12 inches wide, and 2 feet tall, then multiply those numbers directly without converting. You get 576, but that is not 576 of anything useful, because two of the measurements are in inches and one is in feet.

Separately, volume and weight are not interchangeable, even though people often expect a unit converter to handle both. Converting a quantity from gallons to liters changes how you express the volume, nothing more. Weight depends on the density of whatever is filling that volume. A gallon of water and a gallon of honey take up exactly the same amount of space, but the honey weighs quite a bit more.

What Real-World Tasks Depend on an Accurate Volume Calculation?

Volume calculations show up constantly outside of a classroom setting. Freight companies price shipments by cubic feet or cubic meters. Landscaping and construction materials, concrete, mulch, soil, are typically ordered by the cubic yard. Filling a tank or a pool means converting a shape's volume into gallons or liters. And recipes or product packaging sometimes need converting between liters and gallons depending on where you are shopping from.

How Do You Calculate Cubic Feet for Shipping and Freight?

Freight carriers price shipments using cubic feet or cubic meters, commonly abbreviated CBM. To get cubic feet by hand, measure length, width and height in inches, multiply them together, then divide by 1728. Getting this number wrong is not just a math error either, a mismeasured package can trigger a freight reclassification fee once the carrier weighs and measures it themselves. If shipping costs are the main reason you are calculating volume, the cubic feet calculator handles this conversion directly.

How Do You Calculate Cubic Yards for Concrete, Mulch or Soil?

Construction and landscaping materials are almost always priced and ordered by the cubic yard, and one cubic yard equals 27 cubic feet. For mulch or soil specifically, there is an extra step: depth is usually given in inches, so it needs converting to feet before you multiply it by the area you are covering. The cubic yard calculator takes care of that conversion automatically and gives you the amount to order.

How Do You Convert Volume Units Like Gallons and Liters?

One US gallon works out to roughly 3.785 liters. The Imperial gallon, used in the UK and a few other countries, is a different and larger unit, so it is worth double-checking which one a source is using before relying on a figure. If you need to convert between gallons, liters, cubic feet or cubic meters and want the full list of units rather than a single conversion, the volume unit converter covers all of them in one place.

How Do You Calculate the Volume of a Water Tank or Pool?

Tanks and pools use the same shape formulas already covered on this page. Rectangular tanks use length times width times height, and cylindrical tanks use pi times radius squared times height. The main difference is that the result usually needs to be in gallons or liters rather than cubic feet. One wrinkle worth knowing about: for a horizontal cylindrical tank that is not completely full, the usable volume is not a simple fraction of the total, since the cross-section of liquid at a given fill depth is not a full circle. The tank volume calculator supports both rectangular and cylindrical tanks, in full or partial-fill configurations.

How Do You Calculate the Volume of a Partially Filled Tank?

A tank that is completely full or completely empty uses the standard box or cylinder formula without any extra steps. Where it gets more involved is a horizontal cylindrical tank filled partway, because the liquid inside forms a shape called a circular segment rather than a full circle. Working that out by hand means calculating the area of that segment based on the fill depth, then multiplying by the tank's length, which is not something most people want to do with a calculator app and a formula sheet. The same tank volume calculator handles this automatically once you enter the fill depth alongside the tank's dimensions.

How Do You Calculate Dimensional Weight for Shipping?

Shipping carriers charge based on whichever is greater, a package's actual weight or its dimensional weight, sometimes called volumetric weight. Dimensional weight is worked out from the package's cubic size divided by a divisor that varies by carrier. This is a shipping-cost concept rather than a physical volume measurement, but it depends directly on the same length, width and height numbers used to calculate volume. For the full carrier by carrier breakdown, the dimensional weight calculator walks through it.

Frequently Asked Questions

Is a US gallon the same size as an Imperial gallon?

No. The Imperial gallon is about 20 percent larger than the US gallon. One US gallon equals 3.785 liters, while one Imperial gallon equals 4.546 liters, so it is worth checking which one you are working with before relying on a converted figure.

How many cubic feet are in a cubic yard?

27 cubic feet equal one cubic yard, since a cube measuring 3 feet on each side works out to 3 times 3 times 3. This conversion matters most when ordering concrete, mulch or soil, all of which are typically sold by the yard.

Does converting gallons to liters also convert weight?

No. Volume and weight are separate calculations, because weight depends on the density of whatever is filling that volume. A gallon of water weighs around 8.34 pounds, while a gallon of gasoline weighs noticeably less, even though both take up the same amount of space.

How do you calculate the volume of an irregular shape?

Split the shape into simpler pieces you already know how to calculate, such as boxes or cylinders, work out each one separately, then add the totals together. An L-shaped room, for example, can be treated as two rectangular sections.

What is the difference between volume and capacity?

Volume is the total three-dimensional space an object occupies, while capacity refers to how much a container can hold. In everyday use the two are treated as the same number, though technically a container's capacity can be slightly less than its outer volume once the thickness of its walls is accounted for.