Relative Frequency Calculator
Convert raw counts into relative frequencies and cumulative percentages for up to 8 groups.
Useful for frequency tables, surveys, and building probability distributions.
Relative frequency converts raw counts into proportions, making it possible to compare datasets of different sizes. If 200 students sit an exam and 50 score an A, the relative frequency of A is 50/200 = 0.25 (25%). That same rate from a school of 800 students means four times as many A-scorers but the same 25% – which is why relative frequencies travel well between datasets while raw counts do not.
The formula is straightforward: rf_i = f_i / N, where f_i is the count for group i and N is the total across all groups. Each relative frequency falls between 0 and 1, and they must sum to exactly 1.0 (100%). This self-check is a useful sanity check on your data entry.
Cumulative relative frequency adds the proportions in order from first to last group. When data is arranged from smallest to largest, the cumulative value at any point tells you what percentage of observations fall at or below that value. The group where cumulative frequency crosses 0.50 contains the median. Crossings at 0.25 and 0.75 bracket the interquartile range.
Relative frequency tables are the first step in several more advanced tools: frequency polygons, ogive (cumulative frequency) plots, and empirical CDF graphs. Textbooks in statistics, economics, and epidemiology all start here. Enter the count for each group in any order. Blanks are skipped. Negative counts are treated as zero.