Rectangular Prism Calculator
Calculate the volume, total and lateral surface area, space diagonal, and base measurements of a rectangular prism (box) from length, width, and height.
Frequently Asked Questions
How do you find the volume of a rectangular prism?
V = length × width × height. A box measuring 8 × 5 × 3 has a volume of 120 cubic units. Volume is always expressed in cubic units (cm³, m³, ft³) because it fills three dimensions.
How do you find the surface area of a rectangular prism?
SA = 2(lw + lh + wh) — the box has three pairs of identical rectangular faces. For 8 × 5 × 3: SA = 2(40 + 24 + 15) = 158 square units. Lateral surface area (walls only, no top/bottom) is 2(l + w) × h.
What is the diagonal of a rectangular prism?
The space diagonal runs between opposite corners through the inside of the box: d = √(l² + w² + h²), the 3D Pythagorean theorem. For 8 × 5 × 3: d = √98 ≈ 9.90. Useful for checking whether a long object fits inside a box or room.
What is the difference between a rectangular prism, cuboid, and cube?
They describe the same family: a rectangular prism (US term) or cuboid (UK term) is a box with six rectangular faces. A cube is the special case where length = width = height, making all six faces identical squares.