Cuboid Volume Calculator
Find the volume of any rectangular box (cuboid) instantly. Enter length, width and height to get the volume, total surface area and the space diagonal.
V = l × w × h
- 1
Length × width (base area)
8 × 5 = 40 - 2
Base area × height (Volume)
40 × 3 = 120V = l × w × h.
How does this calculator work?
Cuboid volume = l × w × h (all in the same unit). Also gives total surface area = 2(lw + lh + wh) and the space diagonal = √(l² + w² + h²). A cuboid is any rectangular 3-D box; a cube is the special case where all sides are equal.
Formula
How this is calculated
A cuboid is a three-dimensional rectangle where all faces are rectangles and all angles are 90°. Its volume is simply the product of its three perpendicular dimensions: V = l × w × h. Volume tells you how much space the shape occupies — useful for calculating the capacity of a box, the amount of concrete in a slab, the displacement of a rectangular tank, or the space occupied by a piece of furniture.
The total surface area SA = 2(lw + lh + wh) gives the combined area of all six faces, which is used for material estimation (cardboard, wrapping, paint). The space diagonal d = √(l² + w² + h²) is the length of the longest straight line that fits inside the box, from one corner to the opposite corner.
All three dimensions must be in the same unit before applying the formula. The output has the same unit cubed for volume, the same unit squared for surface area, and the same unit for the diagonal. If you need different units, use the volume converter or length converter for final adjustments.
Frequently asked questions
A cuboid is a 3-D solid shape with six rectangular faces, all right-angle corners, and three pairs of parallel congruent faces. It is also called a rectangular prism or rectangular parallelepiped. A cube is the special case where l = w = h.
A face diagonal runs across a single rectangular face: √(l² + w²). The space diagonal runs through the interior of the cuboid from one corner to the diametrically opposite corner: √(l² + w² + h²). It is always the longest internal measurement.
Yes — as long as all three dimensions use the same unit. The volume answer is in that unit cubed (e.g. cm³, ft³, m³) and the surface area is in that unit squared. If dimensions are in mixed units, convert them first.
TG we-Calculate Editorial Team. (2026). Cuboid Volume Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cuboid-volume-calculator
TG we-Calculate Editorial Team. "Cuboid Volume Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/cuboid-volume-calculator.
TG we-Calculate Editorial Team, "Cuboid Volume Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cuboid-volume-calculator
@misc{wecalculate_cuboid_volume_calculator, title = {Cuboid Volume Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cuboid-volume-calculator}}, year = {2026}, note = {TG we-Calculate} }
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