Pie Chart Maker

Worked example: percentages from the 4 seed rows, and the truncation rule

The page loads with four seed rows — housing 40, food 25, transport 20, leisure 15 — summing to 100, so each percentage equals its value directly (40%, 25%, 20%, 15%). Change one row to 0 while the other three stay above 0, and the chart still renders normally; that slice simply takes up no angle in the pie. The "Enter at least one valid row" message only appears when every value is 0 or blank.

A label over 14 characters gets truncated with an ellipsis on the legend (for example, a long category name might show as its first 13 characters plus "…"), while the full text stays in the input field — only the canvas display is shortened. Shortening long labels to 14 characters or fewer before exporting a PNG avoids this.

• The chart title field has a 60-character limit (maxlength="60"); anything past that cannot be typed.
• The color palette cycles through 8 fixed colors; a 9th row reuses the same color as the 1st row.

When a pie chart fits, and when a bar chart is the better call

The pie chart tool has one extra check that the bar chart tool does not: if every value sums to 0 (all blank or all zero), it will not attempt to draw a meaningless full circle. The bar chart tool has no such total check and still tries to draw axes even when every value is 0. That makes the pie chart a better fit for data that must show clear proportions, while the bar chart tolerates rows that are still being filled in.

As a rule of thumb: use the pie chart when there are 2 to 6 categories that add up to a meaningful whole, such as a budget split or survey shares, since proportions are easy to read at a glance. Switch to the bar chart when there are more than 8 categories, the values do not sum to a meaningful 100%, or the point is comparing magnitudes rather than shares, such as monthly sales trends — the pie chart's 8-color palette starts repeating colors once slices exceed 8, making them hard to tell apart.

To verify, manually add up the percentage shown next to every slice; the total should equal 100% (allowing for a tiny rounding difference, since values round to one decimal place). You can also use this site's percentage calculator to compute each value's share of the total separately and cross-check it against the legend.

How to use

1. Enter a chart title (optional).
2. Fill in a label and value on each row.
3. Percentages of the whole and a legend are generated automatically.
4. Click "Export PNG" to download the image.

Use cases

• Show budget or spending category shares.
• Display the share of each survey option.
• Compare market share across products or sources.

Who is it for

• Staff presenting budget or spending shares
• Analysts summarizing survey option proportions
• Teachers and students making proportion charts for reports

Real examples

Good to know

• The chart title field has a 60-character limit; anything beyond that cannot be typed.
• The color palette cycles through 8 fixed colors; entering more than 8 rows repeats colors, leaving legend text as the only way to tell them apart.
• A label longer than 14 characters is truncated with an ellipsis on the legend display, while the full text in the input field is unaffected.