rectangular prism volume calculator
Calculate a rectangular prism's volume in cubic feet, cubic yards, gallons, and liters from length, width, and height.
A rectangular prism is any box-shaped space with three independent dimensions — length, width, and height. Enter all three to get volume in cubic feet, cubic yards, gallons, and liters.
How this calculator works
Rectangular prism volume is length times width times height.
Formula: Cubic feet = L × W × H. Cubic yards = ft³ ÷ 27. Gallons = ft³ × 7.48052. Liters = ft³ × 28.3168.
Worked example
A rectangular prism 8 ft long, 4 ft wide, and 3 ft high:
- Cubic feet: 8 × 4 × 3 = 96.00 ft³
- Cubic yards: 96 ÷ 27 ≈ 3.556 yd³
- Gallons: 96 × 7.48052 ≈ 718.1 gal
- Liters: 96 × 28.3168 ≈ 2718.4 L
Reference
| L×W×H (ft) | Cubic feet |
|---|---|
| 4×3×2 | 24.00 ft³ |
| 8×4×3 | 96.00 ft³ |
| 12×6×4 | 288.00 ft³ |
How to measure
Measure length, width, and height along three perpendicular directions — straight edges, right angles at every corner. This applies to footings, raised beds, storage bins, and rectangular tanks. If all three sides are equal, the Cube Volume Calculator only asks for one measurement.
Frequently asked questions
What's the formula for a rectangular prism's volume?
Volume equals length times width times height: V = L × W × H. It's the same formula as a general box or rectangular space, just framed in geometric terms.
How is a rectangular prism different from the general Volume Calculator?
They compute the same thing — a rectangular prism is the formal name for a box shape. This version is set up for anyone searching the geometric term directly.
Where does this shape come up in construction?
Rectangular footings, raised garden beds, storage bins, foundation walls, and rectangular tanks are all rectangular prisms — any box-shaped volume with straight, perpendicular sides.
What if two of my three dimensions are equal, or all three are equal?
The formula still works fine — equal dimensions just mean two sides of the box match, or (if all three match) the shape is a cube. Use the Cube Volume Calculator if you only need to enter one side length.
Do I need to account for wall thickness for a tank or bin?
This gives the box's outer or inner volume depending on which dimensions you measure. Measure inside dimensions if you want actual holding capacity, and outside dimensions if you're sizing material to build the box itself.
How do I convert this cubic feet result into a concrete order in yards?
Divide the cubic feet result by 27, which the calculator already does — ready-mix concrete is quoted and sold by the cubic yard.
Estimates only. Verify quantities with your supplier before purchasing.