Cuboid Calculator
Calculate cuboid (rectangular prism) volume, total surface area, lateral area, and space diagonal from length, width, and height.
Did this calculation save you time?
Student ProjectHi! I'm a student developer building Calculat in my spare time. I was tired of searching for basic math tools and having to click through 10 spammy popups, loan ads, and cookie trackers.
I keep this website 100% free, private, and ad-free. If this helped you with your homework, project, or finances today, bookmarking this page or telling a friend helps me keep building more free tools!
What Is a Cuboid Calculator?
A cuboid (or rectangular prism) is a convex polyhedron bounded by six rectangular faces. Opposite faces are congruent rectangles, meeting at right angles (90°).
How to Use This Calculator
- Enter length (l), width (w), and height (h).
- View the calculated Volume, Total Surface Area, Lateral Area, and Space Diagonal.
- Review the step-by-step geometric calculations.
Cuboid Volume and Surface Area Formulas
V = lwh, \quad A_{\text{total}} = 2(lw + lh + wh), \quad d = \sqrt{l^2 + w^2 + h^2}Volume is the product of length, width, and height. Total surface area is the sum of the areas of the three pairs of opposing rectangular faces.
Worked Example
Scenario: Calculate cuboid with length l = 8 m, width w = 5 m, height h = 3 m
Volume: V = 8 × 5 × 3 = 120 m³
Surface Area: A = 2 × (8×5 + 8×3 + 5×3) = 2 × (40 + 24 + 15) = 2 × 79 = 158 m²
Lateral Area: A_lat = 2 × 3 × (8 + 5) = 6 × 13 = 78 m²
Space Diagonal: d = √(8² + 5² + 3²) = √(64 + 25 + 9) = √98 ≈ 9.8995 m
Tips & Key Notes
- If length, width, and height are all equal, the cuboid is a cube.
- The space diagonal is the longest straight line segment that fits inside the cuboid.
- Lateral surface area represents the four vertical walls of a room: 2h(l + w).
Frequently Asked Questions
What is the difference between a cuboid and a cube?
A cube is a special cuboid where length, width, and height are identical (all 6 faces are squares).
How do you find the space diagonal of a cuboid?
Apply 3D Pythagorean theorem: d = √(length² + width² + height²).
What is lateral surface area of a cuboid?
It is the area of the four side faces: A_lat = 2h(l + w), excluding the top and bottom faces.
How many edges and vertices does a cuboid have?
A cuboid has 6 faces, 12 edges (4 lengths, 4 widths, 4 heights), and 8 vertices.
Related Calculators
Explore similar toolsCube Calculator
Calculate cube volume, total surface area, lateral surface area, space diagonal, and inradius from side length with step-by-step steps.
Rectangle Calculator
Calculate rectangle area, perimeter, diagonal, and aspect ratio from length and width with complete mathematical steps.
Cylinder Calculator
Calculate right circular cylinder volume, total surface area, lateral (curved) surface area, and base area from radius and height.