**Explanation:**

It’s easy to convert a given fraction into its percentage value.

We need to begin by dividing the numerator of the fraction by its denominator; then, we ought to multiply the value we get by 100.

So for the fraction 1/8 (one-eighth), we need to first divide 1 by 8. The calculations for this are as follows:

After dividing 1 by 8, we get 0.125, which is the decimal form of 1/8.

To get its percentage form, we simply multiply the obtained decimal value by 100:

0.125 x 100 = 12.5

Therefore, one-eighth as a percentage is 12.5%.