Converting a ratio to a percentage involves using division to change the fractional or descriptive ratio to a portion out of 100. For example, the ratio of 1 in 4, which can also be expressed as 1/4, would convert to a percentage through the division of 1 by 4 and then multiplying by 100, equaling 25 percent.
Ratios are commonly used as a more descriptive way to describe a subset of an overall population. A text-based ratio may say "three out of four people prefer this product." When converted to a percentage, that same statistic describing 75 percent of a population could be used in comparison with related measurements.