Pie Chart Generator — Pie & Donut Maker

Three equal slices are 33.333% each, and a chart that rounds each one on its own prints 33%, 33% and 33%. The labels then add up to 99, and someone in the meeting always notices. Every percentage here is rounded so the set adds up to exactly 100, whatever the number of slices or decimals.

Type one slice per line as a label and a number, or paste two columns straight from Excel or Google Sheets. The chart redraws as you type, as a pie or a donut with the total in the middle, and downloads as a PNG for slides or an SVG that stays sharp at any size.

Worked Example: the Household Budget Sample

The page opens on a Monthly Household Budget of seven lines: Rent, 1200, Groceries, 450,Savings, 400, Transport, 180,Utilities, 160, Eating out, 140 andSubscriptions, 35. The total is 2,565, and the shares come out at 46.8%, 17.5%, 15.6%, 7.0%, 6.2%, 5.5% and 1.4%, which sum to 100.0.

Subscriptions gets a legend entry but no label on the pie itself: any slice narrower than about 18 degrees is too thin to hold readable text. SetGroup small slices to Under 2% and nothing changes, because grouping only happens when at least two slices fall under the line; renaming a single slice “Other” would only hide it. Load the class poll sample and the zero-vote line stays in the legend while drawing nothing.

How the Largest-Remainder Method Keeps 100%

Each share is worked out at full precision, then cut down to the chosen number of decimals. The few hundredths left over are handed out one at a time to the slices whose cut-off parts were largest. Three equal slices at one decimal place become 33.4%, 33.3% and 33.3%. The method is the same one used to allocate parliamentary seats, and it moves no slice by more than one unit of the last decimal.

Largest first sorts slices from biggest to smallest, which most chart guides recommend because size is easier to compare clockwise from the top. As typed keeps your order, for data with a natural sequence.

Input Format for Pasted Rows

• The value is the last number on each line; everything before it is the label. Commas, tabs, colons and semicolons all work as the separator.
• Currency signs, thousands separators and a trailing % are ignored, so Rent, $1,200 reads as 1,200. Decimals are fine.
• A line with no number stops with “Line 3: "Q4" has no number at the end. Write it as Label, value.” Negative values are refused, since a pie shows parts of a whole.
• Up to 20 slices are drawn. Past that the extra lines are left out with a note, and a chart that crowded is better as a bar chart anyway.