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Charts from data

CSV to radar chart online

A radar chart puts every criterion on its own spoke and joins the values into a closed shape. It is good at one specific job: showing that two options have different profiles rather than that one is uniformly better. Vendor A wins on speed and features, Vendor B on price and support — that shape difference is what a radar communicates.

Your data never leaves this device

Your data

Paste a table straight from Excel or Google Sheets, or drop a CSV file. Nothing is uploaded anywhere — the whole calculation runs inside this browser tab.

CSV, TSV or plain text. Files saved in windows-1251 are detected and re-read automatically, so Cyrillic headers do not turn into garbage.

Parsing options

Columns

Result

The drawing library is downloaded only when you press the button, and only on this page.

This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.

Facts and limits of this method

Best for Comparing 2–3 options across 4–8 criteria measured on the same scale
Scale requirement All criteria must share one scale — the chart has a single radial axis
Axis count Below 4 the polygon collapses; above 8 the labels crowd the circle
Series limit Two is clear, three is busy, four is unreadable
Fill opacity 18%, so overlapping polygons stay distinguishable
Output PNG at 2× scale, plus CSV, JSON and Markdown

When it misleads you

How it is calculated

The label column becomes the spokes: one axis per row, arranged evenly around the circle. Every numeric column becomes a polygon, drawn by joining its value on each spoke and closing the shape.

The radial axis is shared by every spoke and scaled to the data. This is the format’s hard constraint: there is exactly one scale, so your criteria have to be commensurable before they reach the chart. Ratings from one to ten, percentages, or normalised scores all work; raw mixed units do not.

Fills are drawn at 18% opacity so a polygon underneath another remains visible. Above three series the overlaps stop resolving no matter what the opacity is, which is why the practical ceiling is low.

The tool does not reorder your criteria. That is deliberate — since the order changes the shape, the choice belongs to you rather than to an algorithm sorting alphabetically behind your back.

Questions and answers

Why does one option look so much better than the numbers suggest?

Because you are reading enclosed area, and area grows as the square of the radius. A uniform 20% advantage looks like roughly 44% more ink. Check the exported table before drawing conclusions about the size of a gap.

Can I use criteria measured on different scales?

Not directly — every spoke shares one radial axis. Normalise your columns first, for example to a 0–100 range, using the data normalisation tool.

What do I do about "lower is better" criteria like price?

Invert them before plotting: subtract from the maximum, or use a rank. Otherwise the best price will pull the polygon inward and read as a weakness.

How many criteria are too many?

Past eight the labels start colliding and the polygon becomes a blob. If you have twelve criteria, a grouped bar chart or a simple table will serve the reader better.

Is my data uploaded anywhere?

No. The chart is computed and drawn entirely inside your browser.

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