Calculators & Tools

TOOLS

Quick, free calculators for the math behind charts — percentages, ratios, averages, and more.

Percentage & Ratio

Tool

Percentage Calculator

% of, % change

TOOL
Tool

What is X% of Y?

Percentage of

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Tool

Fraction to Percentage

Fraction → %

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Tool

Ratio to Percentage

A:B → %

TOOL

Statistics & Charts

Tool

Mean, Median, Mode

Averages

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Tool

Standard Deviation

Spread & variance

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Tool

Pie Chart Angles

% ↔ degrees

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Free Chart & Math Tools

These small calculators handle the everyday math that sits behind a good chart — working out what share a number is of a total, converting a fraction or ratio into a percentage for a pie chart, finding the average and spread of a data set, or turning percentages into the exact slice angles a pie chart uses. Each one runs instantly in your browser with no signup. When you have your numbers, turn them into a visual with the chart makers.