Histogram Maker
Paste your numbers and see how they are distributed. Choose the bin count, label the axes, download a PNG.
About this tool
A histogram answers a question a table of numbers cannot: what shape is this data? Paste a column of measurements and the chart shows immediately whether they cluster around one value, spread evenly, lean to one side, or split into two groups. Response times, test scores, part dimensions, session lengths and survey ratings are all easier to read this way than as rows.
The bin count is the one setting that changes what you see, so it is worth a moment. Auto applies Sturges' formula and works well for a few dozen to a few hundred values. Raise it when the distribution looks suspiciously smooth and you think detail is being hidden; lower it when the bars turn ragged and every bin holds one or two points. The vertical axis counts values, so it only ever shows whole numbers.
Everything runs on the page you already have open. Your numbers are parsed, binned and drawn locally, and the PNG export goes through the browser's own Canvas API — nothing is uploaded, nothing sits in a queue behind other users, and no copy of your data is left on a server. For measurements you are not free to share, that is the difference between using a tool and not being allowed to.
Frequently asked questions
What is the difference between a histogram and a bar chart?
A bar chart compares separate categories — sales by region, votes by candidate — and the bars can be reordered without changing the meaning. A histogram shows how one set of numbers is distributed, so the bars sit on a continuous number line and their order is fixed. That is why the bars here touch: each one covers a range of values, and the gap-free axis is what lets you see the shape of the data.
How many bins should I use?
Leave it on Auto unless you have a reason not to. Auto uses Sturges' formula — ceil(log₂(n) + 1) — which gives 7 bins for 40 values, 8 for 100 and 10 for 500. Too few bins hide the shape, too many turn it into noise. If your data is strongly skewed or you have more than a few hundred points, try stepping the count up and watch when the shape stops changing; that is usually the right number.
Is my data uploaded anywhere?
No. The numbers are parsed and the chart is drawn by JavaScript running on this page, and nothing is sent over the network while you work. That matters for lab measurements, salary data, patient readings and anything else you would not paste into someone else's server.
What can I paste in?
A single column of numbers is enough. A header row is detected and skipped automatically, and columns can be separated by tabs, commas or runs of spaces — so pasting straight out of Excel, Google Sheets or a CSV file works without cleanup. Thousands separators, currency symbols and percent signs are stripped, so 1,234 and $1,234.50 and 45% all read as numbers.
Can I save the chart?
Yes. Download PNG re-renders the chart at 2x resolution, so it stays sharp when dropped into a slide deck, a report or a document that scales it afterwards. The export happens in your browser through the Canvas API — the image is never uploaded.