Diagonal of Cube Table: Space diagonal by Side length
Reference table of space diagonal for Diagonal of Cube across a range of side length values — exact, engine-computed figures you can read off at a glance.
Diagonal of Cube Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Space diagonal
8.660254
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Diagonal of Cube Calculator
The Diagonal of Cube Calculator works out your space diagonal in an instant. Enter side length and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the side length.
- Read off your space diagonal — the calculator updates automatically, with no button to press.
Formula
The Diagonal of Cube Calculator uses the formula:
Space diagonal = Side length × √(3)
Worked example
For example, with side length of 5, the space diagonal is 8.660254.
| Side length | 5 |
|---|
| Space diagonal | 8.660254 |
|---|
Results are estimates for educational use, not professional advice.
Frequently asked questions
Multiply the side by √3. A side of 5 gives a space diagonal of about 8.66.
It is the longest line through the cube, from one corner to the opposite corner.
It extends the Pythagorean theorem across three equal dimensions of the cube.
A face diagonal is side × √2 across one face; the space diagonal is side × √3 through the cube.
The Diagonal of Cube Calculator uses the formula: Space diagonal = Side length × √(3). For example, with side length of 5, the space diagonal is 8.660254.
Enter the side length. Read off your space diagonal — the calculator updates automatically, with no button to press.
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