📈 Frequency Polygon Calculator
Enter your grouped frequency data to find each class midpoint, the estimated mean, and which class has the highest frequency — the key building blocks of a frequency polygon.
What a frequency polygon shows
A frequency polygon is a line graph of grouped data: you plot each class’s midpoint against its frequency and connect the points with straight lines. It is a quick way to visualize the overall shape of a distribution, similar to a histogram but easier to compare across multiple datasets on the same chart.
How this calculator works
Enter the lower boundary of your first class, the width used for every class, and the frequency (count) recorded in each of five classes. The calculator computes the midpoint of every class, estimates the overall mean by weighting each midpoint by its frequency, and identifies which class holds the peak of the distribution.
This estimate treats every value in a class as if it sat exactly at the midpoint, which is a standard simplification for grouped data but is not as precise as calculating from raw, ungrouped values. Use it for general educational and planning purposes.