About Histogram Maker
This histogram maker counts every value of the column you choose into bins of equal width and draws a bar for each. It opens with thirty exam scores. It is free, needs no sign-up and runs in your browser, so nothing you enter is uploaded.
The default number of bins follows Sturges' rule, ceil(log2(n) + 1), which gives 6 bins for 30 values; the tallest holds 9 scores. Too few bins hide the shape and too many make it jagged, so try several. Each bin includes its lower edge and excludes its upper edge, except the last, which includes both.
How to use Histogram Maker
- Choose a chart type. The sample table changes to one that suits it until you start editing.
- Replace the sample: edit cells in the grid, paste CSV or tab-separated rows, or choose a CSV or XLSX file.
- Set the title and axis labels, switch the legend and stacking on or off, and pick series colours under Colours.
- For a histogram, choose the column and, if you want, the number of bins. Leave the bins at 0 to let Sturges' rule choose.
- Check the chart, then use PNG or SVG above it to download the image.
Features
- Bar charts, grouped or stacked, with several series from several columns.
- Line and area charts, with stacked areas for parts of a whole over time.
- Pie and doughnut charts with percentages in the legend.
- Scatter plots with several y series against one x column.
- Histograms with an adjustable bin count, and box plots with whiskers and outliers.
- An editable data grid that scrolls sideways on phones.
- CSV, TSV and XLSX upload, read in a Web Worker so the page stays responsive.
- Series colours chosen from a fixed set that stays readable in light and dark mode.
- PNG and SVG export with a white background.
Worked examples
30 scores from 42 to 94 gives 6 bins of width 8.67
The range 94 - 42 = 52 is divided by the number of bins.
Privacy: how it works
- Your table is read and drawn by code running in this browser tab. Files are not uploaded and no chart is stored anywhere.
Tips
- Keep the label column first and leave out total rows, or the total will be drawn as one more bar.
- Text in a number column, such as "n/a", turns that cell into zero on bar and line charts. Clear the cell if you want a gap in your data instead.
- For presentations, SVG keeps lines crisp when the slide is scaled. PNG is easier to paste into documents.
- If your numbers use a thousands separator, remove it first: 1,200 is read as text, 1200 as a number.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial and no credit card. Ulkaa Tool does the work with your own device, so there is no server bill to pass on to you.
Do I need an account?
No. There is no sign-up and no login. Open the page and use it. An Ulkaa account is not needed for anything on this tool.
Does it run in my browser?
Yes. Your data are processed by code running in your browser tab, on your own device.
Is my data uploaded?
No. Your data are never sent to Ulkaa or to anyone else. You can check this yourself by watching the Network tab in your browser developer tools while you use the tool.
How many bins should I use?
Start with the automatic choice, which uses Sturges' rule, then try a few more and a few fewer. A good histogram shows one clear shape without every bin jumping up and down.
More Chart Maker pages
- Chart MakerPaste or upload a table, pick a chart type and download the chart as PNG or SVG.
- Bar Graph MakerCompare categories with grouped or stacked bars and download the graph.
- Stacked Bar Chart MakerStack several series on each bar to show parts of a total.
- Line Graph MakerShow change over time with one line per column.
- Area Chart MakerFill the space under each line to show volume and parts of a whole.
- Pie Chart MakerTurn labels and positive numbers into slices of one whole.
- Doughnut Chart MakerA pie chart with a hollow centre, from labels and positive numbers.
- Scatter Plot MakerPlot pairs of numbers to see how two measurements relate.
- Box Plot MakerCompare the spread of several groups with one box per number column.