Percentages are what readers look for first on a pie chart: “Chrome has about 60% of the visits.” To get them, divide each category by the total and multiply by 100. With 1,310 Chrome visits out of 2,200, Chrome’s slice is 1,310 ÷ 2,200 = 59.5% of the pie.
Sometimes you only have the chart – for example a pie in a textbook or report with angles marked. Measure each angle and divide by 3.6 to recover the percentage: a 90° slice is a quarter, 25%. Switch the input to angles and the calculator does that for you, checking that the angles add up to 360°.
Labels on published charts are usually rounded to whole numbers or one decimal, and rounding each slice separately often makes the labels add up to 99% or 101%. This calculator uses largest-remainder rounding so the displayed percentages always total exactly 100%, and adds a cumulative column – handy for statements such as “the top two browsers account for 76.3% of visits”.
How to use the Pie Chart Percentage Calculator
- Categories – one “label, value” per line — Counts, amounts or slice angles, e.g. “Safari, 370”.
- The values are
- Round to — Rounded values are adjusted (largest-remainder method) so they still add up exactly.
- Order of slices
Everything is calculated in your browser, so results appear instantly and nothing you type is sent to a server.
How it works
The values (or angles) on each line are added to give the total; each is divided by the total and multiplied by 100. Percentages are rounded to the chosen precision while keeping their sum at exactly 100%, and the cumulative column adds them in the order shown.
Worked example
A website had 2,200 visits: Chrome 1,310, Safari 370, Edge 260, other browsers 140 and Firefox 120. Chrome’s share is 1,310 ÷ 2,200 = 0.5955 → 59.5%, Safari 16.8%, Edge 11.8%, other 6.4% and Firefox 5.5% (to one decimal, summing to 100%). The cumulative column shows that Chrome and Safari together account for 76.3% of the visits. Measured on the chart, Chrome’s slice would be 0.5955 × 360° ≈ 214.4°.
Angle to percentage conversions
| Angle | Percentage |
|---|---|
| 18° | 5% |
| 36° | 10% |
| 45° | 12.5% |
| 54° | 15% |
| 60° | 16.7% |
| 72° | 20% |
| 90° | 25% |
| 120° | 33.3% |
| 180° | 50% |
| 270° | 75% |
Formula
Percentage = value ÷ total × 100% · Percentage from an angle = angle ÷ 360° × 100% = angle ÷ 3.6 · Cumulative % = running sum of percentages
Worked example
Inputs — Categories – one "label, value" per line: Chrome, 1310
Safari, 370
Edge, 260
Firefox, 120
Other, 140; The values are: Counts or amounts; Round to: 1 decimal place; Order of slices: As entered.
Results — Percentage of each slice = Chrome 59.5% · Safari 16.8% · Edge 11.8% · Firefox 5.5% · Other 6.4%; Percentage table = Category Value Percent Cumulative % Decimal
───────────────────────────────────────────────────
Chrome 1,310 59.5% 59.5% 0.5955
Safari 370 16.8% 76.3% 0.1682
Edge 260 11.8% 88.1% 0.1182
Firefox 120 5.5% 93.6% 0.0545
Other 140 6.4% 100% 0.0636
Total 2,200 100% 1; Total of the values = 2,200; Number of slices = 5; Largest share = Chrome (59.55%); Smallest share = Firefox (5.45%).
Key terms
- Percentage
- A share of the whole expressed out of 100.
- Cumulative percentage
- The sum of the percentages up to and including a category.
- Decimal share
- The proportion of the whole as a number from 0 to 1.
Frequently asked questions
How do I calculate the percentage for a pie chart?
Divide each value by the total and multiply by 100. 370 of 2,200 → 16.8%.
How do I convert a pie chart angle to a percentage?
Divide the angle by 3.6. 72° → 20%, 54° → 15%, 120° → 33.3%.
How do I get the value from a percentage if I know the total?
Multiply: 25% of 420 is 105. And 5% of 420 is 21, which would be an 18° slice.
Why do my pie chart percentages add up to 99% or 101%?
Each one was rounded separately. Largest-remainder rounding – used here – fixes that by giving the leftover 0.1% to the slice that lost most in rounding.
What is a cumulative percentage?
The running total of percentages: 59.5%, then 59.5% + 16.8% = 76.3%, and so on, ending at 100%.
What does a 75–25 pie chart look like?
One slice covering three quarters of the circle (270°) and one covering a quarter (90°).
Can percentages in a pie chart exceed 100%?
No. All slices together are exactly 100%; if your percentages add up to more, the categories overlap and a pie chart is the wrong choice.