# Pie Chart Percentage Calculator

URL: https://speedycalculator.com/calculators/statistics/pie-chart-percentage/
Last updated: 2026-10-30

> The pie chart percentage calculator converts category counts – or slice angles measured from an existing chart – into percentages of the whole, rounded so they add up to exactly 100%, with cumulative percentages, decimal shares and a redrawn pie chart.

## Inputs

- 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

## Results

- Percentage of each slice
- Note
- Percentage table
- Pie chart
- Total of the values
- Number of slices
- Largest share
- Smallest share

## Formula

```
Percentage = value ÷ total × 100% · Percentage from an angle = angle ÷ 360° × 100% = angle ÷ 3.6 · Cumulative % = running sum of percentages
```

## Explanation

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

AnglePercentage18°5%36°10%45°12.5%54°15%60°16.7%72°20%90°25%120°33.3%180°50%270°75%

## 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.

## FAQ

**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.


## Sources

- [OpenStax – Introductory Statistics 2e](https://openstax.org/details/books/introductory-statistics-2e)
- [Khan Academy – Statistics and probability](https://www.khanacademy.org/math/statistics-probability)