What is the difference between area and volume?

Area measures two-dimensional space (length x width) in square units. Volume measures three-dimensional space (length x width x height) in cubic units.

How do I convert cubic feet to gallons?

Multiply cubic feet by 7.4805 to get US gallons. For example, 282.74 cubic feet equals approximately 2,115 gallons.

Volume Calculator

Q: How many cubic feet are in a cubic yard?

There are 27 cubic feet in 1 cubic yard (3 ft x 3 ft x 3 ft = 27 cu ft). Divide by 27 to convert cubic feet to cubic yards.

Free online volume calculator with 6 shapes — box, sphere, cylinder, cone, pyramid, and pipe. Get accurate cubic feet, cubic meters, or cubic yards with instant unit conversions and reference charts.

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Cu Inches

Cu Yards

Cu Meters

Liters

Gallons

What Is Volume?

Volume is the measure of three-dimensional space occupied by an object, expressed in cubic units (cu ft, cu m, or cu yd). It represents the total capacity or space within a solid shape — like how much air fills a room, water fills a tank, or concrete fills a foundation.

Volume calculations are essential for construction, shipping, manufacturing, HVAC system sizing, tank capacity planning, and countless other real-world applications. Whether you're calculating the volume of a cylinder for a water tank, a box for a shipping container, or a pipe for plumbing, accurate volume estimates prevent material waste and ensure proper sizing.

This calculator supports 6 common 3D shapes — box (cuboid), sphere, cylinder, cone, pyramid, and pipe (hollow cylinder) — with instant conversion between cubic feet, cubic inches, cubic yards, cubic meters, liters, and US gallons.

Volume Formulas & Examples

Below are formulas and examples for all 6 supported shapes. Each includes common use cases and quick reference estimates.

📦 Box (Cuboid)

V = L x W x H

Example: 10 ft x 8 ft x 6 ft = 480 cu ft

Common Uses: Rooms, boxes, shipping containers, storage

Quick: 10x10x10 box = 1,000 cu ft

Conversion: 480 cu ft = 13.6 cu m = 3,590 gal

⚪ Sphere

V = 4/3 x π x r³

Example: r = 5 ft -> 4/3 x π x 125 = 523.6 cu ft

Common Uses: Tanks, balls, domes, planets

Quick: 10 ft diameter sphere ~ 524 cu ft

Conversion: 523.6 cu ft = 14.8 cu m = 3,917 gal

🥫 Cylinder

V = π x r² x h

Example: r = 3 ft, h = 10 ft -> π x 9 x 10 = 282.74 cu ft

Common Uses: Water tanks, pipes, columns, drums

Quick: 6 ft diameter x 10 ft = ~283 cu ft

Conversion: 282.74 cu ft = 8 cu m = 2,115 gal

🔺 Cone

V = 1/3 x π x r² x h

Example: r = 3 ft, h = 9 ft -> 1/3 x π x 9 x 9 = 84.82 cu ft

Common Uses: Traffic cones, funnels, piles, roofs

Quick: Cone is 1/3 of a cylinder's volume

Conversion: 84.82 cu ft = 2.4 cu m = 634 gal

🔻 Pyramid

V = 1/3 x Base Area x Height

Example: Base = 6x6 ft, h = 10 ft -> 1/3 x 36 x 10 = 120 cu ft

Common Uses: Roofs, monuments, tents, architectural features

Quick: Pyramid is 1/3 of a box's volume

Conversion: 120 cu ft = 3.4 cu m = 898 gal

🛢️ Pipe (Hollow Cylinder)

V = π x (R² − r²) x h

Example: R=4, r=3, h=10 -> π x (16-9) x 10 = 219.91 cu ft

Common Uses: Pipes, tubes, hoses, conduits, ducts

Quick: Subtract inner from outer cylinder area

Conversion: 219.91 cu ft = 6.2 cu m = 1,645 gal

Common Volume Reference

Quick reference for everyday volume measurements.

1 cu ft

7.48 gallons

1 cu yd

27 cu ft

1 cu m

35.3 cu ft

1 liter

0.0353 cu ft

1 gallon

0.134 cu ft

1 cu ft water

62.4 lbs

Std bathtub

~42 cu ft

55-gal drum

7.35 cu ft

How to Measure Volume

Accurate volume measurement is essential for construction, shipping, and manufacturing. Follow these guidelines for precise results:

Use consistent units: Measure all dimensions in the same unit (feet, meters, or yards) before calculating
For boxes: Measure length, width, and height at the widest points — interior dimensions for capacity, exterior for shipping
For cylinders: Measure the radius (half the diameter) and the height — for water tanks, measure interior dimensions
For spheres: Measure the diameter and divide by 2 to get the radius — or measure circumference and divide by 2π
For pipes: Measure both outer and inner radius (or diameter) — wall thickness matters for hollow volumes
For irregular shapes: Use water displacement or break into regular shapes and sum their volumes
Account for wall thickness: For tanks and pipes, interior volume (capacity) is smaller than exterior volume
Measure multiple times: Take each measurement at least twice to verify accuracy

When Do You Need Volume Calculations?

Volume calculations are critical in many professional and DIY scenarios:

Construction: Concrete volume for foundations, slabs, columns, and walls — ordering by cubic yards
HVAC: Duct sizing and air volume calculations for heating and cooling systems
Plumbing: Pipe volume for water flow rates, tank sizing, and drainage systems
Shipping & Logistics: Cargo volume for containers, trucks, and freight — dimensional weight pricing
Manufacturing: Material volume for injection molding, casting, and 3D printing
Agriculture: Grain bin volumes, silo capacity, irrigation tank sizing
Pool & Spa: Water volume for chemical dosing, heating requirements, and filtration sizing

Volume Unit Conversions

Quick reference for converting between common volume units.

Unit	Abbreviation	1 cu ft =	1 cu m =	1 cu yd =
Cubic Feet	cu ft / ft³	1	35.315	27
Cubic Meters	cu m / m³	0.0283	1	0.765
Cubic Yards	cu yd / yd³	0.037	1.308	1
Cubic Inches	cu in / in³	1,728	61,024	46,656
Liters	L	28.317	1,000	764.6
US Gallons	gal	7.481	264.17	202

Frequently Asked Questions

What's the difference between volume and area?

Area measures two-dimensional space (length × width) in square units — like the floor of a room. Volume measures three-dimensional space (length × width × height) in cubic units — like how much air fills the entire room. Area is flat, volume is solid.

How do I calculate the volume of a cylinder in gallons?

First calculate the volume in cubic feet using V = π × r² × h. Then multiply by 7.4805 to convert cubic feet to US gallons. For example, a cylinder with r = 3 ft and h = 10 ft has a volume of 282.74 cu ft, which equals approximately 2,115 gallons.

How many cubic feet are in a cubic yard?

There are 27 cubic feet in 1 cubic yard (3 ft × 3 ft × 3 ft = 27 cu ft). To convert cubic feet to cubic yards, divide by 27. To convert cubic yards to cubic feet, multiply by 27. Concrete is typically ordered by cubic yard.

How do I calculate the volume of an irregular shape?

For irregular shapes, use the water displacement method: submerge the object in a container of water and measure the volume of water displaced. Alternatively, break the irregular shape into regular shapes (boxes, cylinders, cones), calculate each volume separately, and add them together.

What's the volume of a standard 55-gallon drum?

A standard 55-gallon drum has an approximate volume of 7.35 cubic feet. The typical dimensions are about 22.5 inches in diameter and 34.5 inches in height. Actual volume may vary slightly by manufacturer and drum type.

How much does a cubic foot of water weigh?

One cubic foot of fresh water weighs approximately 62.4 pounds at room temperature. Sea water is slightly heavier at about 64 pounds per cubic foot due to dissolved salts. This is important for calculating dead weight loads on structures and vessels.

Do I measure interior or exterior dimensions for tank volume?

For capacity (how much the tank can hold), always measure interior dimensions. For displacement or shipping volume, measure exterior dimensions. The difference can be significant — for example, a concrete water tank with 6-inch thick walls has much less interior capacity than its exterior size suggests.

What is the formula for pipe volume?

Pipe volume is calculated using the hollow cylinder formula: V = π × (R² - r²) × h, where R is the outer radius, r is the inner radius, and h is the length. For the interior capacity only, use V = π × r² × h with r as the inner radius. This is critical for plumbing, hydraulics, and flow rate calculations.