Histogram Maker

Class	Freq.	Relative	Cum.	Cum. %
[40, 50)	4	3.3%	4	3.3%
[50, 60)	19	15.8%	23	19.2%
[60, 70)	32	26.7%	55	45.8%
[70, 80)	34	28.3%	89	74.2%
[80, 90)	22	18.3%	111	92.5%
[90, 100]	9	7.5%	120	100%
Total	120	100%

Class

Freq.

Relative

Cum.

Cum. %

[40, 50)

3.3%

[50, 60)

15.8%

19.2%

[60, 70)

26.7%

45.8%

[70, 80)

28.3%

74.2%

[80, 90)

18.3%

111

92.5%

[90, 100]

7.5%

120

100%

Total

120

100%

How to make a histogram in 4 easy steps

Add your data. Type or paste your raw numbers into the data box, separated by commas, spaces or new lines. Copying a column from Excel or Google Sheets works too, or import an .xlsx / .csv file and pick a column.
Choose your bins. The histogram maker picks sensible bins automatically. Open the Bins tab to use a different rule, or set the exact bin width, number of bins and starting value.
Label and style it. Add a title and axis labels, pick a theme or color palette, and switch on extras like a normal curve, frequency polygon or mean line.
Download or share. Export a sharp PNG, JPG, SVG or PDF up to 4K, copy the frequency table into your report, or send a link so others can open and edit a copy.

What is a histogram?

A histogram is a chart that shows the distribution of numerical data. The range of values is split into equal intervals called bins (or classes), and the height of each bar shows how many values fall into that bin. Because the bins sit next to each other on a continuous number line, the bars of a histogram touch, unlike the separate bars of a bar graph.

A histogram lets you see at a glance where most values lie, how spread out they are, whether the data is symmetric or skewed, and whether there are gaps or outliers. Read more in What is a histogram?

Why this is the easiest histogram maker online

Paste anything: comma-, space- or line-separated numbers, a column from a spreadsheet, or an Excel / CSV file. Files are read on your device, never uploaded.
Smart bins: Sturges, square-root, Rice, Scott and Freedman–Diaconis rules, rounded to clean numbers like 10, 20, 30, or your own bin width and start.
Every histogram type: frequency, relative frequency, percent, density and cumulative.
Built-in analysis: a frequency distribution table plus mean, median, mode, standard deviation, quartiles and skewness.
Overlays: normal curve, frequency polygon or ogive, and mean and median lines.
Compare data sets: up to 6 data sets on shared bins, overlapping, side by side or stacked.
High-resolution export: PNG, JPG, SVG and PDF up to 3840px wide, with no watermark.
Autosave, share & embed: your work is saved in your browser, and a link or embed code puts an interactive histogram on any website.

How to choose the number of bins

The number of bins changes the story a histogram tells. Too few bins hide the shape of the data; too many make it look noisy. These are the rules built into the tool:

Rule	Formula	Best for
Sturges	k = log₂(n) + 1	Small to medium, roughly normal data (the default)
Square root	k = √n	Quick estimates; used by Excel and many textbooks
Rice	k = 2·∛n	Larger data sets
Scott	h = 3.49·s·n^(−1/3)	Normally distributed data
Freedman–Diaconis	h = 2·IQR·n^(−1/3)	Skewed data and data with outliers

Here n is the number of values, k the number of bins, h the bin width and s the standard deviation. Whatever rule you pick, try a few bin widths: if the overall shape stays the same, you can trust it.

How to read the shape of a histogram

Symmetric (bell-shaped): most values sit in the middle and taper off evenly on both sides, like heights or exam scores. The mean and median are close together.
Skewed right: a long tail stretches to the right, as with incomes, house prices or reaction times. The mean is larger than the median.
Skewed left: the tail stretches to the left, as with scores on an easy test. The mean is smaller than the median.
Bimodal: two peaks, which often means two different groups are mixed together.
Uniform: bars of roughly equal height, as with rolls of a single fair die.

Load the examples under the data box (exam scores, reaction times, customer ages, dice rolls) to see each shape.

Histogram vs. bar graph

Histogram	Bar graph
Shows the distribution of numerical (continuous) data	Compares separate categories
Bars touch, because bins cover a continuous range	Bars have gaps between them
Bin order is fixed by the number line	Bars can be sorted in any order
Built from raw values grouped into bins	Each bar is one value you already have

Making a histogram in other software

Software	How
Excel	Insert › Insert Statistic Chart › Histogram. Full Excel guide
Google Sheets	Insert › Chart, then Chart type › Histogram. Google Sheets guide
TI-84	STAT PLOT › histogram › ZOOM 9. TI-84 guide
Desmos	histogram(L, 5). Desmos guide
Python	plt.hist(data, bins=10). Python guide

Tips for a clear histogram

Use clean bin edges. Widths like 5, 10 or 0.5 starting at a round number are far easier to read than 7.31.
Keep bins equal width. Unequal bins distort the picture unless you switch the y-axis to density.
Label the axes with units, such as “Height (cm)”, and say what the y-axis counts.
State the sample size in the subtitle, for example “n = 120 students”.
Compare fairly. When comparing groups with different sizes, use relative frequency or percent instead of counts.

Frequently asked questions

Is this histogram maker really free?

Yes. Every feature is free, including custom bins, the frequency table, statistics, normal curve, 4K downloads and PDF export. There is no sign-up, no watermark and no limit on how many histograms you make.

How do I make a histogram from Excel or Google Sheets data?

Select the column of numbers in your spreadsheet, copy it and paste it into the data box. You can also click 'Import Excel / CSV' (or drag a file onto the data box) and pick the column you want. Files are read in your browser and never uploaded.

How many bins should a histogram have?

A common starting point is Sturges' rule, k = log₂(n) + 1, which gives about 8 bins for 100 values. The square-root rule (k = √n) gives more bins. For skewed data or data with outliers, the Freedman–Diaconis rule is usually best. You can switch between all of these in the Bins tab, or set the exact number of bins or bin width yourself.

What happens to a value that falls exactly on a bin boundary?

By default each bin includes its lower boundary and excludes its upper one, written [a, b), so 20 is counted in the 20–30 bin. The last bin also includes its upper boundary so the maximum is never lost. You can switch to (a, b] in the Bins tab if your textbook uses that convention.

Can I make a relative frequency or cumulative histogram?

Yes. In the Bins tab, choose Frequency, Relative, Percent or Density for the y-axis, and switch on 'Cumulative histogram' for running totals. There are also dedicated relative frequency and cumulative frequency histogram makers.

How do I add a normal curve (bell curve) to my histogram?

Open the Design tab and switch on 'Normal distribution curve'. A bell curve fitted to your data's mean and standard deviation is drawn over the bars, scaled to match the y-axis.

Can I compare two or more data sets?

Yes. Click 'Add data set' to add up to 6 data sets. They share the same bins, and you can show them overlapping, side by side or stacked. The Double Histogram Maker starts with two data sets ready to compare.

Which file formats can I download?

PNG (with optional transparent background), JPG, SVG and PDF, each at Standard (1200px), Full HD (1920px) or 4K (3840px) width. You can also copy the frequency table straight into Excel or Word, or download it as CSV.

Is my data private?

Yes. Your histogram is built entirely in your browser and saved only in your browser's local storage. Nothing is uploaded to a server. Share links contain the data inside the link itself.

Does it work on phones and tablets?

Yes. The histogram maker works in any modern browser on iPhone, Android, iPad, Chromebook, Mac and Windows. Nothing needs to be installed.

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