Pie Chart Calculator
Enter 30, 45, and 25, and this pie chart calculator returns three slices worth exactly 108, 162, and 90 degrees. A pie chart calculator turns a list of category values, like survey responses, budget line items, or vote counts, into the percentage and angle each category needs to be drawn as a slice of a circle. Type your values separated by commas, in any unit you like: dollars, votes, hours, or units sold. The values do not need to add up to 100 first. If your categories are 120, 80, 50, and 50, the calculator adds them to a total of 300 and works out each slice's true share from there. Every slice gets two numbers back, its percentage of the whole and its angle in degrees, which is the number a spreadsheet, presentation tool, or design app needs to draw that wedge on a 360 degree circle.
Quick answer
A full circle is 360 degrees, so a slice's angle equals its percentage of the total multiplied by 3.6.
Slices calculated
3slices
Total of all values
100
| Slice | Value | Percentage | Degrees |
|---|---|---|---|
| Slice 1 | 30 | 30% | 108° |
| Slice 2 | 45 | 45% | 162° |
| Slice 3 | 25 | 25% | 90° |
Percentages are rounded to 2 decimals per slice, so the column may not sum to exactly 100%. Degrees show each slice's angle on a 360 degree pie chart.
What this tells you
- •A full circle is 360 degrees, so a slice's angle equals its percentage of the total multiplied by 3.6.
- •You do not have to pre-convert values to percentages first. Enter raw numbers, like sales figures or survey counts, and the calculator finds the total for you.
- •Percentage = (slice value / total of all values) x 100.
- •Degrees = (slice value / total of all values) x 360, the same result as percentage x 3.6.
- •A value of 0 is a valid entry. It produces a 0% slice that takes up no space on the chart, useful for a category with no responses in a given period.
- •Percentages are rounded to 2 decimal places per slice and may not add up to exactly 100.00. A chart with three equal slices totals 99.99%, not 100.00%, because each slice rounds on its own. This is expected and does not affect the chart itself.
- •At least 2 values are required. A pie chart with a single slice is just a full circle with nothing to compare it against.
How to Use
- 1Enter your category values separated by commas, for example 30, 45, 25 or 120, 80, 50, 50.
- 2Use any consistent unit across the list: dollars, votes, hours, units sold, or percentages that already sum to 100.
- 3Review the percentage and degree columns for each slice in the results table below the calculator.
- 4Copy the degree values into a spreadsheet, slide deck, or design tool when you draw the chart by hand or build a custom SVG.
- 5Change a value and recheck the table. Every percentage and angle updates instantly as the total shifts.
How It Works
Formula
percentage = (value / total) x 100, degrees = (value / total) x 360Add every value in the list to get the total. Each category's percentage is its value divided by that total, multiplied by 100. Its angle in degrees is that same share of the total multiplied by 360, since one full pie chart is one full circle. The two formulas are proportional: multiplying a percentage by 3.6 gives the matching degree value directly, without recalculating from the raw values. For a list of 30, 45, and 25, which already sums to 100, the 45 slice is 45% of the chart, and 45 x 3.6 = 162 degrees.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Three categories that already sum to 100
The values already total 100, so each percentage matches the value itself: 30%, 45%, 25%. Multiplying each by 3.6 gives the degrees: 108, 162, and 90, which add up to a full 360 degree circle.
Four raw values that do not sum to 100
The values total 300, not 100, so the calculator normalizes first. 120 / 300 = 40%, 80 / 300 = 26.67%, and each 50 is 16.67%. In degrees that is 144, 96, 60, and 60, which also sum to a full 360.
A category with zero responses
A zero value is entered on purpose to represent a category that got no responses in a survey. It shows as a 0% slice with 0 degrees, while the remaining 100 total is split between the other two categories at 60% and 40%.
Three equal slices and the rounding note
Each value is exactly one third of the total, so every slice rounds to 33.33% and every angle rounds to a clean 120 degrees. The percentages sum to 99.99% due to rounding, but the degrees still add up to a full 360 because 120 x 3 is exact.
A four-category household budget
A $1,000 monthly budget split into rent (500), food (300), transport (150), and savings (50) becomes 50%, 30%, 15%, and 5% of the pie, or 180, 108, 54, and 18 degrees.
Percentage to Degree Conversion
Quick reference for turning a slice's percentage share into its angle on a 360 degree pie chart.
| Percentage | Degrees |
|---|---|
| 10% | 36° |
| 16.67% | 60° |
| 25% | 90° |
| 33.33% | 120° |
| 50% | 180° |
| 75% | 270° |
| 100% | 360° |
Multiply any percentage by 3.6 to get its degree value directly, without recalculating from the raw values.
Why Percentages and Degrees Both Matter for a Pie Chart
A percentage tells you how big a category is relative to the whole, which is what most people read off a pie chart at a glance. The degree value is what actually draws the slice, since a circle is measured in 360 degrees and a wedge's size on the page is set by its angle, not by the percentage number printed on a label.
Most chart tools, from spreadsheet software to design programs, calculate the angle automatically once you hand them raw values. This calculator is useful when you need to see that math directly, for example when drawing a chart by hand, coding a custom SVG or canvas pie chart, checking a chart a tool already generated, or explaining to a class how percentages translate into angles.
Because percentage and degrees are directly proportional, converting between them is a single multiplication, percentage times 3.6, or degrees divided by 3.6. Knowing that shortcut makes it easy to sanity check any pie chart without redoing the full calculation from the original values.
Common mistakes
- Assuming the values must already sum to 100. Raw counts, dollar amounts, and survey tallies work just as well, since the calculator finds the total and normalizes every slice against it.
- Entering a negative value to represent a decrease or a debt. A pie chart slice cannot have a negative size, so a negative entry is rejected. Use a bar chart or a separate note instead for negative figures.
- Expecting rounded percentages to sum to exactly 100.00%. Each slice is rounded to 2 decimals on its own, so a total of 99.98% or 100.01% across all slices is normal and does not mean the math is wrong.
- Leaving out a category with a value of 0. Omitting it changes the total and shifts every other slice's percentage. Enter it as 0 to keep the category visible in the chart with an accurate 0% share.
- Mixing units within one list, like entering some values in dollars and others already converted to percentages. Every value in the list needs to represent the same kind of quantity for the percentages to mean anything.
- Trying to chart a single value alone. A pie chart needs at least two categories to compare, since one slice with nothing to divide it against is just a full circle.
Embed this calculator on your site
Drop this single line where you want the calculator to appear. It is responsive, mobile-friendly, resizes automatically, and is free to use with attribution.
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