A chart from your numbers, drawn here CHART

Every free chart maker is a data upload with a picture attached

You paste a column of figures into a text box on somebody else's server and you get back a PNG. That is the transaction, and it is fine right up until you notice what the column usually is: figures about people, about money, about headcount, about something nobody agreed could leave the building.

The chart is the last step before a document goes to a board, a regulator or a court, which means the numbers in it are usually the most sensitive version of themselves: final, checked, and attributable. Uploading them to a free service to be drawn is a thing people do without thinking about it once.

This draws the SVG in the page and hands it to you. And SVG rather than PNG on purpose: it is a vector, so it stays sharp at any size and prints properly, it can be edited afterwards in any drawing program, and it is a file you own rather than a link that expires.

Three places it is opinionated, and says so

A bar starts at zero. Always. The length of a bar is the quantity; that is the whole grammar of the form. A bar chart with a cut axis is not a chart with a caveat, it is a picture of a different number, and it will be read as the number it looks like. If you need to show a small difference between large values, a line chart does that honestly, and this will happily draw you one.

A pie chart is for parts of one whole, and not many of them. People are poor at comparing angles and much better at comparing lengths, which is why almost every pie would be a clearer bar chart. Two or three slices adding to a meaningful total is the case where a pie earns its place.

The axis says what it is. An unlabelled axis, or one without units, is the commonest fault in charts that are otherwise fine, and it is the one that makes a chart useless the moment it is separated from the paragraph it was written under, which is immediately, because charts get screenshotted.

Before you use it

Say what the chart is for in one sentence before you choose a type. If the sentence is a comparison, use bars. If it is a change over time, use a line. If it is a relationship between two quantities, use points. Choosing the type first and finding the message afterwards is how a deck ends up full of charts nobody can summarise.

Then check it says what you think. Cover the title and look at the picture: if the shape alone suggests something different from your sentence, the chart is wrong, not the reader.

And give the numbers with it. A chart is a summary and somebody will want the underlying figures. Keep the data beside the picture so the next person does not have to ask, or reconstruct them off the page.

Nearby: the guide on why a bar chart starts at zero makes the argument in full, FIGURES handles rounding and significant figures, Sheets holds the numbers, and CONTRAST checks the colours can be told apart by somebody who does not see them as you do.