About the rectangular prism calculator
A rectangular prism (cuboid, box) has three independent dimensions. Enter any three values, for example length, width and volume to get the height of a tank, and the rest are derived.
Volumes are also converted to litres and gallons, which is handy for tanks, aquariums and shipping boxes.
Formulas
| Volume | V = lwh |
| Surface area | S = 2(lw + lh + wh) |
| Space diagonal | d = √(l² + w² + h²) |
Frequently asked questions
How do I find the volume of a box?
Multiply the three dimensions: V = l × w × h.
How many litres does a box hold?
Compute the volume in cm³ and divide by 1000 (1 L = 1000 cm³). The results panel does this conversion automatically.