UtilibyWritten by the Utiliby editorial team · Last updated October 31, 2026 · Rules and formulas reviewed October 2026 · اقرأ بالعربية
What this free average calculator does
People search for an average calculator to add up scores, work out typical prices, check a class mean or find a grade. The word average usually means the mean, but median and mode are also averages, and each tells a different story. This free online tool gives all three at once for any list of numbers, together with the count, sum, range, quartiles, interquartile range, variance, sample and population standard deviation, geometric and harmonic means, and an outlier check.
A histogram marks the mean and the median so you can see how the numbers are spread. A weighted average tab handles grades and scores where some items count more, and a missing number tab tells you what you need on the next test to reach a target average. Paste numbers from a spreadsheet or type them in; nothing is uploaded.
How to use the average calculator
- Enter your numbers, separated by commas, spaces or new lines.
- Read the mean, median and mode at the top.
- Check the spread with the range, quartiles and standard deviation.
- Look at the histogram to see the shape of the data and where the mean and median sit.
- Use the weighted average tab for grades or scores with different weights.
- Use the missing number tab to find the score needed for a target average.
Mean, median and mode explained
The mean adds all the values and divides by the count. For 12, 15, 15, 18, 22, 25, 31 and 95 the sum is 233 and the mean is 29.125. The median is the middle value of the sorted list, which for these eight numbers is the average of 18 and 22, or 20. The mode is the most frequent value, here 15. Because one value, 95, is far larger than the rest, the mean is pulled well above the median. In this situation the median is a better description of a typical value.
| Measure | Value | Meaning |
|---|---|---|
| Mean | 29.125 | Sum divided by count |
| Median | 20 | Middle of the sorted list |
| Mode | 15 | Most common value |
| Range | 83 | Largest minus smallest |
| Std deviation (sample) | 27.33 | Typical distance from the mean |
Range, quartiles and standard deviation
An average alone does not show how varied the data are. The range is the largest minus the smallest value. Quartiles divide the sorted data into four parts. Q1 is the median of the lower half, and Q3 the median of the upper half. For the example list Q1 is 15 and Q3 is 28, so the interquartile range is 13. Standard deviation measures how far values typically sit from the mean. The population version divides by n and is used when you have every value. The sample version divides by n minus 1 and is used for a sample from a larger group. For the example they are 25.56 and 27.33.
Spotting outliers
An outlier is a value far from the rest. A common rule flags anything below Q1 minus 1.5 times the IQR or above Q3 plus 1.5 times the IQR. In the example the upper fence is 28 + 1.5 x 13 = 47.5, so 95 is flagged. Outliers may be errors, rare events or real extremes, so investigate them before removing anything. The calculator tells you when an outlier is pulling the mean away from the median.
Weighted averages and grades
In a weighted average each value counts in proportion to its weight. Suppose coursework scores 90 and counts 40 percent, a project scores 80 and counts 30 percent, and an exam scores 70 and counts 30 percent. The weighted average is (90 x 40 + 80 x 30 + 70 x 30) / 100 = 81, while the plain average of the three scores is 80. Weights can be percentages, credit hours or any positive numbers, since the tool divides by their total.
Finding a missing number or the score you need
If you want an average of 85 across five tests and have already scored 80, 90, 85 and 88, the total you need is 85 x 5 = 425. You have 343, so the last test must be 82. The same method works for any target and any number of remaining scores, in which case the tool gives the average needed from each. It is useful for exams, sales targets and fitness goals.
Geometric and harmonic means
The geometric mean multiplies the values and takes the nth root. It is used for growth rates, indexes and ratios. If an investment grows 10 percent one year and 30 percent the next, the geometric mean growth is about 19.6 percent, not 20 percent. The harmonic mean suits averaging rates, such as speeds over equal distances. Both need positive numbers, so the calculator shows them only when every value is above zero.
Common uses
- School and university grades and class means.
- Price and cost comparisons.
- Sports and fitness statistics.
- Survey and research summaries.
- Business metrics such as average order value.
- Checking data quality by looking for outliers.
Accuracy, privacy and responsible use
The calculator handles up to 20,000 numbers and uses standard formulas. Quartiles use the median-of-halves method, and other methods can give slightly different values. Statistics describe data and do not prove cause. Nothing you enter leaves your browser.
Related free tools
Use these free online tools together with this one:
- Turn averages and changes into percentages with the percentage calculator.
- Calculate a grade point average with the GPA calculator.
- Work with fractions and mixed numbers using the fraction calculator.
- Average your pay across periods with the hourly to salary calculator.
- Test whether two averages truly differ with the A/B test calculator.
Frequently asked questions
How do I calculate the average of a set of numbers?
Add the numbers and divide by how many there are. For 12, 15, 15, 18, 22, 25, 31 and 95 the sum is 233 and there are 8 numbers, so the mean is 233 / 8 = 29.125.
What is the difference between mean, median and mode?
The mean is the sum divided by the count. The median is the middle value when sorted. The mode is the value that appears most often. They can differ a lot when the data is skewed.
How do I find the median?
Sort the numbers and take the middle one. With an even count, average the two middle numbers. For 12, 15, 15, 18, 22, 25, 31 and 95 the middle pair is 18 and 22, so the median is 20.
How do I find the mode?
Count how often each value appears. The most frequent value is the mode. There can be more than one mode, or none if every value is different.
What is the range?
The largest value minus the smallest. For the example, 95 - 12 = 83.
What is standard deviation?
A measure of how spread out the numbers are around the mean. A small value means the numbers cluster tightly. The tool gives the sample and population versions.
Sample or population standard deviation?
Use the population formula, dividing by n, when your list is every value you care about. Use the sample formula, dividing by n - 1, when it is a sample from a larger group.
What are quartiles and the interquartile range?
Q1 is the median of the lower half and Q3 the median of the upper half. The interquartile range is Q3 minus Q1 and measures the spread of the middle half of the data.
How are outliers detected?
With the 1.5 x IQR rule. A value is flagged if it is below Q1 minus 1.5 x IQR or above Q3 plus 1.5 x IQR. In the example the upper fence is 47.5, so 95 is an outlier.
What is a weighted average?
An average where some values count more than others. Multiply each value by its weight, add them and divide by the total weight. Scores of 90, 80 and 70 weighted 40, 30 and 30 give 81.
How do I calculate my grade average?
Use the weighted average tab with each score and its weight. Weights can be percentages, credits or any positive numbers.
How do I find a missing number for a target average?
Multiply the target by the total count and subtract the sum of known numbers. To average 85 over five tests after scoring 80, 90, 85 and 88, you need 85 x 5 - 343 = 82.
What is the geometric mean?
The nth root of the product of n positive numbers. It suits growth rates and ratios. The harmonic mean, shown too, suits rates like speed.
Can I paste numbers from a spreadsheet?
Yes. Paste a column or row. Commas, spaces, tabs and new lines all work, and currency or percent signs are ignored.
Why is the mean different from the median?
Extreme values pull the mean toward them but barely move the median. A few very high salaries, for example, raise the mean far above the median.
Is my data stored or sent anywhere?
No. Everything runs in your browser.
Is this average calculator free?
Yes. It is free to use online with no sign-up.
Sources and further reading
- Khan Academy, Summarizing quantitative data.
- NIST/SEMATECH, Engineering Statistics Handbook: outliers.
- Wolfram MathWorld, Mean.
- Wolfram MathWorld, Standard deviation.
Sources were consulted in October 2026. Standards and rules can change, so always check the official page for your situation.