DIY Cost Tools
Cube Calculator
MATH & GEOMETRY CALCULATOR
Calculate cube volume, surface area, and face and space diagonals.
Use the same length unit throughout. All fields are required. Use the rectangular prism tool when the three dimensions differ. This model excludes wall thickness.
How to use this calculator
Enter your dimensions and select Calculate. Length results use your input unit, areas use its square, and volumes use its cube. Retain measurement precision until the final answer.
Formula and explanation
V = s³; area = 6s²; face diagonal = s√2; space diagonal = s√3
Every edge of a cube has the same length.
Worked example
For Edge length (units) = 4, results are Volume (cubic units): 64; Surface area (square units): 96; Face diagonal (units): 5.6568542; Space diagonal (units): 6.9282032.
Important limitations
Use the rectangular prism tool when the three dimensions differ. This model excludes wall thickness.
Ideal geometry does not account for manufacturing tolerances or measurement uncertainty. This is a calculation aid, not a structural design or building-code approval. Absolute inputs must not exceed one trillion.
Frequently asked questions
Can I enter centimeters?
Yes; volume is then in cubic centimeters and area in square centimeters.
Why two diagonals?
One crosses a face; the other crosses the interior.
Can I mix inches and centimeters?
Convert all lengths to one unit first. Mixed units produce incorrect results.
Why did my result disappear?
Blank, invalid, or out-of-range inputs clear the previous result and display an instruction.
Review notes
Reviewed October 1, 2026. Default results were checked against the displayed formulas. Script tests covered blank, negative, nonfinite, and excessive inputs. Results run locally in your browser.