Percentage Calculations

Computing what fraction of a total a value represents, expressed as a percentage.

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Computing what fraction of a total a value represents, expressed as a percentage.

A percentage expresses a value as a fraction of 100. To find what percentage a part is of a whole: divide the part by the total, then multiply by 100. Percentages are fundamental to pie charts (which always sum to 100%) and for comparing proportions across different totals.

percentage = (part / total) × 100

15 out of 60 = 15/60 × 100 = 25%
If a pie slice is 40°, it represents 40/360 × 100 ≈ 11.1%
200 out of 800 total = 200/800 × 100 = 25%

How to recognize it

Questions asking 'what percentage' or 'what fraction'
Pie chart slices (each represents a percentage)
Comparisons asking for relative size

Common mistakes

Dividing total by part instead of part by total
Forgetting to multiply by 100
Confusing percentages with absolute values

Step-by-step walkthrough

A survey asked 60 people about their favorite beverage. 15 people said coffee. What percentage prefer coffee?

Look at the pie chart - we need to find what percentage the Coffee slice represents
Identify the part (Coffee lovers) and total: Part = 15, Total = 60
Apply the percentage formula: (part ÷ total) × 100
Calculate: 15 ÷ 60 = 0.25
Multiply by 100: 0.25 × 100 = 25%

Answer: 25%

Practice guidance

Data Interpretation