Average Percentage Calculator
Enter two or more percentages to find their average, simple or weighted by group size.
Updated
Average Percentage Calculator
Our Average Percentage Calculator finds the mean of two or more percentages. Use a simple average when every percentage counts the same, or switch to a weighted average when the percentages come from groups of different sizes, such as classes, credits or tests with different totals.
Quick answer
The average of percentages is their sum ÷ how many there are: (80 + 90 + 70) ÷ 3 = 80%.
- Weighted: Σ(percentage × weight) ÷ Σ weight
- Use weights when the percentages come from groups of different sizes
- 50% of 4 and 90% of 400 average to 70% simply, but 89.6% weighted
- Negative percentages such as −5% work too
What Is an Average Percentage?
An average percentage is a single percentage that represents a set of percentages. The simple (arithmetic) average adds them up and divides by how many there are, so every value counts equally. Three test scores of 80%, 90% and 70% average to 80%.
If the percentages describe groups of different sizes, a weighted average gives each one a share that matches its size.
How to Calculate the Average of Percentages
- Add the percentages. 60 + 75 + 88 + 94 = 317.
- Count them. There are 4.
- Divide the sum by the count. 317 ÷ 4 = 79.25%.
For averages of plain numbers, use the Average Calculator.
Weighted Average Percentage
Multiply each percentage by its weight, add the results and divide by the total weight. Grades of 85% (3 credits), 92% (4 credits) and 78% (2 credits):
3 + 4 + 2 = 9
779 ÷ 9 ≈ 86.56%
The simple average of the same grades is 85%, because it ignores that the 92% course carries the most credits.
When a Simple Average Is Wrong
A class of 4 students has a 50% pass rate and a class of 400 has a 90% pass rate. The simple average says 70%, but the true pass rate across all 404 students is:
= 36,200 ÷ 404
≈ 89.6%
Use group sizes as weights whenever you want the overall rate. Use the simple average only when each percentage should count the same, such as equally weighted assignments.
Averaging Test Scores With Different Totals
You scored 18 out of 20 (90%) and 35 out of 50 (70%). The simple average is 80%, but your share of all the marks is lower:
= 53 ÷ 70 ≈ 75.71%
You get the same answer by entering 90 and 70 with the total marks (20 and 50) as weights.
Average Percentage Examples
| Percentages | Average |
|---|---|
| 80%, 90%, 70% | 80% |
| 50%, 90% | 70% |
| 85%, 92%, 78% | 85% |
| 60%, 75%, 88%, 94% | 79.25% |
| 12.5%, 15%, 17.5% | 15% |
| −5%, 10%, 3% | 2.67% |
Common Mistakes
- Ignoring group sizes. Averaging rates from groups of different sizes needs weights.
- Mixing totals. Scores out of 20 and out of 50 do not count equally toward total marks.
- Averaging compound growth. Yearly growth of −5%, 10% and 3% averages 2.67%, but the compound rate is about 2.48% a year.
- Dividing by the wrong count. Count every value you added, including any 0%.
Key Terms
- Mean
- Sum ÷ count, the simple average.
- Weight
- How much a value counts, such as a group size.
- Weighted
- Σ(value × weight) ÷ Σ weight.
- Median
- The middle value once sorted.
How to Use the Average Percentage Calculator
- Choose Simple or Weighted. Simple counts every percentage the same. Weighted adds a weight box to each row, such as a group size, credits or total marks.
- Enter the percentages. Type one percentage per row, such as 80, 90 and 70. Press Add percentage for more rows (up to 20), or paste a list such as 80, 90, 70 to fill the rows at once. Empty rows are skipped.
- Read and copy the result. The average appears as you type, with the working, the median and the range (and the simple average for comparison in Weighted mode). Press Copy to copy it, or Clear or Esc to start again.
Example: pass rates of 50% in a class of 4 and 90% in a class of 400. Simple gives 70%. Switch to Weighted and enter 4 and 400 as the weights: the result is about 89.6%, the real pass rate across both classes.
Who Can Use This Calculator?
Frequently Asked Questions (FAQs)
How do you calculate the average of percentages?
Add the percentages and divide by how many there are. (80 + 90 + 70) ÷ 3 = 240 ÷ 3 = 80%.
Can you average percentages?
Yes, if each percentage should count the same. If they come from groups of different sizes, use a weighted average with the group sizes as weights, or the result will not match the overall percentage.
How do you calculate a weighted average percentage?
Multiply each percentage by its weight, add the results and divide by the total weight. 85% × 3 + 92% × 4 + 78% × 2 = 779, and 779 ÷ 9 ≈ 86.56%.
What is the average of 80%, 90% and 70%?
The average is 80%, because 80 + 90 + 70 = 240 and 240 ÷ 3 = 80.
How do I average test scores with different total marks?
Weight each percentage by the test total, or add up all the marks. 18/20 (90%) and 35/50 (70%) give 53 ÷ 70 ≈ 75.71%, not 80%.
Why is my average percentage different from the overall percentage?
A simple average gives every group the same say. A 50% pass rate in a class of 4 and 90% in a class of 400 average to 70%, but 89.6% of all 404 students passed.
What should I use as weights?
Use whatever each percentage is measured out of: the number of people in each group, course credits, total marks or sales volume.
Can I average growth rates or negative percentages?
Yes. −5%, 10% and 3% average to 2.67%. For growth that compounds year after year, the compound annual rate (about 2.48% here) describes the overall change more accurately.
Is the Average Percentage Calculator free?
Yes. It is completely free, needs no sign-up, and can be used as many times as you like.
Try our Average Percentage Calculator to average any set of percentages, simply or weighted by group size.