Histogram Maker

Histogram Maker, Generator, or Creator: All the Same Tool

People search for this a dozen different ways and they all want one thing, a chart from a list of numbers without installing anything. Whether you are after a histogram maker, a histogram generator, a frequency histogram creator, a frequency chart maker, or just want to create a histogram online, this is it. Free, no account, nothing uploaded.

A histogram is a chart that groups numbers into ranges called bins and draws a bar for how many values land in each range. Because the bars cover ranges rather than separate categories, they touch with no gaps. That is the one thing that separates a histogram from a bar chart.

What this histogram maker does

Paste a column or a comma-separated list of numbers and this tool draws the histogram right away. It groups your values into bins, counts how many fall in each, and shows the bars, a frequency table, and the summary statistics all at once. Nothing is uploaded, and it works on your phone.

The one thing most histogram tools get wrong

A histogram is only as honest as its bins. Too few bins and you flatten real detail; too many and you turn noise into fake peaks. Most makers pick one bin count and hide the choice from you. This one puts it front and center: switch between Sturges, Freedman-Diaconis, Scott, Rice, square-root, or a manual bin count and watch the shape update instantly, so you can see how the binning changes the story before you trust it.

It Is Also a Frequency Distribution Table Generator

The chart is not the only output. Every time you paste data, the tool builds the full frequency distribution table underneath it, with a row per bin and five columns:

Column	What it holds
Bin start	Lower edge of the class interval
Bin end	Upper edge of the class interval
Count	Absolute frequency, how many values fall in the bin
Relative %	That count as a share of the total
Cumulative %	Running share up to and including that bin

So if you came looking for a frequency distribution table maker, a frequency distribution calculator, a class interval generator, or a relative frequency table, you do not need a second tool. You can also flip the chart itself from counts to relative frequency with the display dropdown, and copy the whole table out to paste into a report or a spreadsheet.

For the theory behind those columns, frequency, relative and cumulative frequency works through how each one is calculated and when to use which. The frequency distribution table page covers building one by hand, and relative frequency histogram covers the percentage version specifically.

Bin, Class, Interval: The Vocabulary

Textbooks and software disagree on names for the same thing, which makes searching for help harder than it should be:

• A bin is the same as a class, a class interval, or a range
• Bin count or number of classes is how many bars you end up with
• Bin width or class width is how wide each range is
• Bin edges or class boundaries are the cut points between them
• Frequency is the count in a bin, sometimes called absolute frequency to distinguish it from relative

A "bin graph" and a histogram are the same chart. How to choose bins goes deeper on picking the count, and what is a histogram covers the definition and the parts.

How to read a histogram

Each bar covers a range of values, called a bin, and its height is how many data points land in that range. Because the bars represent ranges, they sit right next to each other with no gaps. That is the main difference from a bar chart, where each bar is a separate category.

• A single central hump that tapers both ways is bell-shaped, close to a normal distribution.
• A long tail to the right is right (positive) skew; a long tail to the left is left (negative) skew.
• Two humps usually means two groups are mixed together.
• Flat bars mean a roughly uniform spread.

Each of those has its own page with worked examples: histogram shapes is the index, and it splits into bell shaped, right skewed, left skewed, bimodal, uniform, and symmetric. If you need to name the shape for homework, how to read a histogram walks through describing one in words. Histogram vs bar chart covers the distinction in full.

Choosing the number of bins

The default here is Sturges' rule, which sets the bin count to ceil(log2 n) + 1. It works well for small, roughly normal datasets. For skewed data or data with outliers, Freedman-Diaconis is more robust because it uses the interquartile range instead of the full spread. When in doubt, try two or three methods and keep the one that shows the structure most clearly without inventing spikes.

Worked example

Say you have the ages of 20 people. With Sturges' rule that is 6 classes. The mean age is 42.8 and the median is 43, which are close, so the data is fairly symmetric. Paste your own list above, pick a method, and download the chart as a PNG or SVG when it looks right.

If you have to produce the chart in a specific program rather than here, how to make a histogram in Excel covers the Analysis ToolPak and the newer chart route, how to make a histogram in Python covers matplotlib, pandas and seaborn, and how to make a histogram covers doing it by hand on paper.