Maths - Cuboids

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This page allows you to calculate every dimension of a Cuboid, if you know enough dimensions already. The actual shape that you are interested in can be any physical object whatsoever, possibly a container, or a foundation slab, or to work out how much space your shopping will take up.
Click on any of the links at the top of the page to reveal (or hide) more information about this calculator.


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A three-dimensional object with six, sides in parallel pairs. Opposite sides therefore have the same length and width, and all corners are right angles (90 degrees.)
A special kind of cuboid where all six sides are squares of equal size. All of the formulae on this page can be applied to Cubes in exactly the same way as for Cuboids.
Length l / Width w / Height h
The distance measured along an edge of the Cuboid. In this context which one is considered Length and which one the Width or Height is entirely irrelevant. If you need to complete several calculations to add the results together, it may be important for you to be consistant.
Diagonal 1, 2 & 3
The distance between either of the opposite corners of a face of the Cuboid.
Internal Diagonal
The distance between any of the opposite corners inside the Cuboid. This will always be the single largest dimension of the object.
Face Circumferance Cf
The distance measured once around a face of the Cuboid. For a perfect cube, all three faces will be the same, but for an irregular cuboid, there will be three different values.
Total Circumferance Ct
The total length of all edges of the cuboid.
Face Area Af
The size of each face of the cuboid. For a perfect cube, all three faces will be the same, but for an irregular cuboid, there will be three different values. Opposite sides will always be identical.
Total Surface Area At
The surface area of all six faces of the Cuboid added together. For an open-topped box, subtract the area of the top surface from this value.
Volume v
The space enclosed by the Cuboid.



  1. Fill in as many boxes as you can with the values that you know
  2. Choose the correct units for all 'input' fields, or leave as 'Units' if not required
  3. Choose the correct units for any output fields that you require
  4. Click the 'CalcResult' button below the input fields
  5. The value of the blank fields will be calculated
  6. A 'Results Area' will be displayed below.
  7. All known values will be shown. (Values for which insufficient information was given will also be identified.)
  8. To do further calculations simply change any values in the input fields and click the 'CalcResult' button again. (Press the 'Clear Form' button if you want to empty all of the input fields.)
  9. Press the 'Clear Results' button if you wish to discard the first results, otherwise further calculations will be added into the same area.
  10. Click the 'CalcResult' button again
Diagram showing dimensions


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