What is a cube of a number?
The cube of a number is that number raised to the power of 3 — in other words, the number multiplied by itself three times: \(x^{3} = x \times x \times x\). The name comes from geometry: the volume of a cube with edge length x is exactly \(x^{3}\). This calculator cubes any real number you enter and shows the full multiplication so you can follow the math.
How to use this calculator
Type the number you want to cube into the x field and read the result. The tool accepts whole numbers, decimals, negative numbers, and scientific E-notation (for example, 1.5E3 means 1500). It returns the cubed value, a written-out solution in the form \(n^{3} = n \times n \times n = \text{result}\), and tells you whether the input is a whole number (in which case the result is a perfect cube).
The formula explained
Because the exponent 3 is odd, cubing preserves the sign of the input. A positive number cubed stays positive; a negative number cubed becomes negative. For example, $$(-2)^{3} = -2 \times -2 \times -2 = -8.$$ We compute the cube by direct multiplication (\(n \times n \times n\)) rather than a power function, which keeps the sign exact and avoids floating-point issues with negative bases.
Worked example
Cube the number 4: $$4^{3} = 4 \times 4 \times 4 = 64.$$ Since 4 is a whole number, 64 is a perfect cube. Another example: $$1.5^{3} = 1.5 \times 1.5 \times 1.5 = 3.375,$$ which is not a perfect cube because the input is not an integer.
FAQ
What does -2³ mean? By math convention, \(-2^{3}\) means \(-(2^{3}) = -8\), while \((-2)^{3}\) also equals \(-8\). In this tool you enter the actual signed value, so entering -2 cubes -2 directly to get -8.
What is a perfect cube? A perfect cube is the cube of an integer, such as 1, 8, 27, 64, or 125. If your input is a whole number, the result is a perfect cube.
Why does my huge number look approximate? Extremely large inputs can exceed standard double-precision range, so results beyond roughly \(10^{15}\) may be shown in approximate or scientific form.
