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Histogram

A histogram maker for how a pile of numbers spreads

A histogram is not a bar chart of named categories. It takes many raw measurements and counts how many fall into each interval. The shape is the point: a pile in the middle, a long tail, two humps, a cliff at a passing score. This page accepts a list of numbers, lets you choose the number of bins, and exports PDF, PNG, or JPEG.

How to bin the numbers

Paste the measurements into the numbers field. Commas, spaces, and line breaks all separate values. You do not name each number. A quiz score, a delivery time, or a price belongs in the list as a bare value. The chart finds the lowest and highest and cuts that range into equal bins. The height of each bar is how many values landed in that bin. The label under the bar is the start of the interval.

The bin count changes the story. Too few bins and every shape looks like a single lump. Too many bins and a small class looks jagged because each bar is one or two students. Start near the square root of how many numbers you have, then move the bin control until the shape is stable. If the shape flips every time you add one bin, you do not have enough data for a fine histogram. Say the class size in the subtitle.

There is no series and no slice. Color is one color, because every bar is the same kind of count. The vertical axis is the count. Title it Students, Days, or Items so a bar of 6 means something. The horizontal axis is the measurement. Title it Score or Minutes. Grid lines help someone see that one bin is about twice another. Value labels help when the counts are the figures you will discuss.

A histogram hides the individual. You cannot point at a bar and recover a name. If you need the names, use the table maker. If you need each point as a pair of measurements, use the scatter plot. If you need the median and the quartiles of a few groups rather than every bin, use the box plot. Those tools are in the grid under this article.

Check the list for a stray zero or a stray extra digit before you export. One 410 in a list of scores out of 100 will stretch the axis and flatten the real pile into the first bin. PDF is the print, PNG is the sharp picture, and JPEG is the fallback. The numbers stay in this browser. Reset restores the sample quiz. Replace it with your own list before you share the file.

All tools

The table maker is still here. These charts are for the picture of the same numbers: parts, trends, spread, and rank. Open any chart, change the sample, and download PDF, PNG, or JPEG.