Average Percentage Calculator
Averaging percentages is simple arithmetic — add them and divide by the count — but it is only meaningful when each percentage carries equal weight. This calculator gives the simple average plus the median and count, and the notes below explain when you should weight instead.
Results
Formula
How to use this calculator
- Enter your percentages as plain numbers (no % sign needed).
- Press Calculate.
- Check the notes: if the percentages came from groups of different sizes, use a weighted average instead.
Worked example
Average 80%, 90% and 100%.
- Sum: 80 + 90 + 100 = 270.
- Divide by the count: 270 ÷ 3 = 90.
Result: The average is 90%.
Frequently asked questions
When is a simple average of percentages wrong?
When the percentages describe groups of different sizes. 90% of 10 students and 50% of 100 students do not average to 70% overall — the true overall rate is (9 + 50) ÷ 110 ≈ 53.6%.
How do I compute a weighted average of percentages?
Convert each percentage back to counts (rate × group size), add the counts, and divide by the total group size. Our Weighted Grade Calculator applies the same principle to grades.
Can I average percentages over 100%?
Yes, the arithmetic works the same. Just be sure every figure measures the same kind of thing before averaging them.
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