Rectangular box or prism
Use length × width × height for a box. For a cube, enter the same edge length in all three fields.
Read the guide: How to calculate rectangular container volumeFree geometry and capacity tool
Volume calculator
Choose a shape and enter dimensions in mm, cm, m, inches or feet. Get cubic units, liters and US gallons, with the formula shown.
Add the volumes of several containers
Calculate and add each container, using any shape or unit. Each click adds one container.
Copy your list before leaving: closing or reloading the page clears it.
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Method
How to get a dependable answer
- Choose the matching 3D shape. Measure the object itself for solid volume, or the inside space for container capacity.
- Use one unit for every field: cm gives cm³, inches gives in³ and feet gives ft³. Enter 5 ft 6 in as 5.5 ft.
- Select radius or diameter to match your measurement. For a cylinder or cone, use perpendicular height, not slant height.
- Calculate, check the cubic-unit result, and use the liter or US-gallon conversion when you need liquid capacity.
Shapes
Which shape should you choose?
Cylinder
Use the radius or diameter and perpendicular height for a circular cylinder. For a full pipe, use its inside diameter and length.
Read the guide: How to calculate cylinder volume in litersSphere
Use the radius or diameter of a complete sphere, such as a ball. Container capacity requires the inside measurement.
Read the guide: How to calculate sphere volume in litersCone
Use the circular base radius and perpendicular height. A cone with its tip cut off is a frustum and needs a different formula.
Read the guide: How to calculate conical frustum volume in liters1 L = 1,000 cm³
Conversions used to check the result
One liter is exactly 1,000 cm³, while one cubic meter is 1,000 liters. For millimeters, inches or feet, each length is converted to meters before the shape formula is applied, preventing mixed-unit calculations.
Calculated result
How to use the answer responsibly
Geometric volume versus usable capacity
The main figure describes an ideal shape. A fish tank loses capacity to glass thickness, substrate and equipment, while a storage tank may have curved corners, pipes or a lower operating fill line. Work from inside dimensions, then make adjustments that match the real container.
A quick independent check
A container measuring 36 × 18 × 16 inches has a geometric capacity of about 170 liters, or roughly 45 US gallons. Repeating the calculation in cubic inches and converting the final value is a useful way to catch a misplaced decimal or an incorrect unit selection.
When geometry is not enough
Do not rely on a simple estimate for structural loading, pressure, chemical dosing, medical use or regulatory compliance. Compare the result with manufacturer documentation, a calibrated vessel, a meter reading or qualified advice. Keep the unrounded value until the final step when small differences matter.
Volume formulas by shape
Volume measures the space occupied by a three-dimensional object. For a hollow container, its inside dimensions describe capacity. Choose the formula that matches the shape; length × width × height applies to a rectangular box, not to every object.
V is volume; l, w and h are length, width and perpendicular height; a is a cube’s edge; r is radius. If you measure diameter d, use r = d ÷ 2. Keep every dimension in the same unit.
Scroll horizontally to see every column.
| Shape | Volume formula | Measurements to use |
|---|---|---|
| Rectangular prism / box | V = l × w × h | Length, width and height at right angles. Also called a cuboid. |
| Cube | V = a³ | One edge length, a. In this calculator, choose Rectangular box / prism and enter a in all three fields. |
| Cylinder | V = πr²h | Circular base radius and perpendicular height. Use inside measurements for a tank or pipe. |
| Sphere | V = 4πr³ / 3 | Radius from the center to the surface, or half the diameter. |
| Cone | V = πr²h / 3 | Base radius and perpendicular height from the base to the tip; do not use the sloping side. |
Worked examples: cubic feet and cubic centimeters
Box volume in cubic feet
A rectangular box is 3 ft long, 2 ft wide and 1 ft high. Multiply the three dimensions to find 6 ft³. The liter conversion describes the same geometric space.
3 × 2 × 1 ≈ 6 ft³
≈ 169.901 L
Cylinder volume from radius and height
A cylinder has a radius of 5 cm and a height of 20 cm. Its diameter is 10 cm, so either radius 5 or diameter 10 gives the same answer. Keep π unrounded until the final result.
π × 5² × 20 ≈ 1,570.796 cm³
≈ 1.571 L
Convert cubic units to liters
| Volume | Exact equivalent in liters |
|---|---|
| 1 cm³ | 0.001 L |
| 1 m³ | 1,000 L |
| 1 in³ | 0.016387064 L |
| 1 ft³ | 28.316846592 L |
| 1 US gal | 3.785411784 L |
Length conversion factors must be cubed for volume: 1 ft = 12 in, so 1 ft³ = 1,728 in³. US liquid gallons differ from Imperial gallons. “Liter” and “litre” name the same unit.
Volume calculator questions
How do I calculate volume from dimensions?
Identify the three-dimensional shape first. For a rectangular box, multiply length × width × height. For a cylinder, multiply π × radius² × height. Dimensions in centimeters produce cm³; dimensions in feet produce ft³.
Can I calculate a cube with this tool?
Yes. Choose Rectangular box / prism and enter the same edge length for length, width and height. A cube with 10 cm edges has volume 10³ = 1,000 cm³, exactly 1 liter.
How do I enter feet and inches?
Select ft and use decimal feet: 5 ft 6 in is 5 + 6/12 = 5.5 ft. Alternatively, select in and enter 66. Use the selected unit for every dimension; do not enter 5.6 for 5 ft 6 in.
Can I convert square feet or square meters to volume?
You also need a height, depth or thickness. For a uniform layer, volume = area × thickness. An area of 12 ft² with a thickness of 0.5 ft has a volume of 6 ft³. Area alone does not determine volume.
How do I find the volume of an irregular object?
Split it into measurable shapes, add their volumes, and subtract overlaps or cavities. For a suitable small object, water displacement is another method. The four geometric models here do not directly model arbitrary curves or partially filled horizontal tanks.
Is volume the same as capacity or weight?
Volume describes space; capacity usually describes the usable inside space of a container. Weight is a different quantity: converting liters to mass requires the material’s density. For usable capacity, account for actual fill level and displaced contents.
Method and references
The tool uses ideal geometric formulas and converts dimensions before calculating. Reference examples are rounded to three decimal places; the calculator keeps intermediate precision.