The cube root of a number is the value that, multiplied by itself three times, gives that number, so the cube root of 27 is 3. The browser-based square root calculator also computes the cube root to high precision, entirely in your browser with nothing uploaded.
The cube root of a number x is the value that gives x when raised to the third power, meaning multiplied by itself three times. The cube root of 8 is 2 because 2 times 2 times 2 is 8, and the cube root of 27 is 3. Unlike square roots, cube roots are defined for negative numbers too, since a negative value cubed stays negative; the cube root of -8 is -2.
Most cube roots are irrational and need a calculator for a useful number of decimal places. The square root calculator reports the cube root alongside the square root of the same input, so you can look up both at once. It runs locally in your browser, which keeps whatever number you enter private.
Yes. A negative number has a real cube root, because a negative value multiplied by itself three times stays negative.
The cube root is calculated to high precision, which matters because most cube roots are irrational.
No. The calculation happens entirely in your browser.