Data summary
10, 12, 12, 15, 18, 21, 21, 21, 25Mean = 17.2222222222, median = 18, mode = 21, range = 15
Statistics Calculator
Use this free statistics calculator to summarize one data set with count, sum, mean, median, mode, min, max, range, quartiles, IQR, sample variance, population variance, standard deviation, steps, copy, and history.
Inputs to checkExample numbersCopyable answerTab-only history
Statistics summary9 values
- Mean
- 17.2222222222
- Count
- 9
- Sum
- 155
- Median
- 18
- Mode
- 21
- Range
- 15
- Min
- 10
- Max
- 25
- Q1
- 12
- Q3
- 21
- IQR
- 9
- Population variance
- 23.950617284
- Population SD
- 4.8939367879
- Sample variance
- 26.9444444444
- Sample SD
- 5.1908038341
Steps
- Sort the data: 10, 12, 12, 15, 18, 21, 21, 21, 25.
- Add all values for sum 155 and divide by 9 to get the average.
- Use the middle value for the median and most frequent value for the mode.
- Subtract min 10 from max 25 for the range.
- Use Q3 minus Q1 for IQR: 21 - 12 = 9.
- Average squared distances from the mean for population variance; divide by 8 for sample variance before taking the square root.
Recent answers
Recent answers will appear here.
Input tips
Separate values with commas, spaces, or new lines.
The full summary includes spread, quartiles, and standard deviation.
How to use the Statistics Calculator
- Enter a list of numbers separated by commas, spaces, or line breaks.
- Press Calculate statistics to see count, sum, mean, median, modes, range, quartiles, IQR, variance, and standard deviation.
- Review the sorted values, Q1/Q3, and sample versus population spread before copying.
- Use examples, recent answers, or copy the summary while comparing one data set at a time.
What people use it for
Summarize one list of data values in a result card before writing homework notes or reports.
Find center, spread, quartiles, sample standard deviation, and population standard deviation together.
Check class scores, survey responses, measurement lists, experiment trials, and spreadsheet columns.
Compare mean and median when a high or low outlier may be pulling the average.
Use Q1, Q3, and IQR to describe the middle half of a data set without relying only on the extremes.
Copy descriptive statistics into notes while keeping count, sum, mode, variance, and rounding visible.
Quick examples
Classic spread check
2, 4, 4, 4, 5, 5, 7, 9Mean = 5, median = 4.5, population SD = 2, sample SD = 2.1380899353
No repeated values
4, 8, 15, 16, 23, 42No mode; range = 38
Exam scores
88, 92, 94, 94, 99Mean = 93.4, median = 94, mode = 94, sample SD = 3.9749213829
Two modes
3, 3, 5, 7, 7, 9Modes = 3 and 7, median = 6, range = 6
Decimals and negatives
-2, 0, 1.5, 1.5, 4Mean = 1, mode = 1.5, range = 6
Same value repeated
12, 12, 12Range = 0, standard deviation = 0
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Statistics CalculatorSee slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- CalculatorsBrowse related calculators and utilities in the same category.
- Calculator and utility guidesFind more guides that use real tool inputs and example numbers.
- All free toolsSearch every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Quick answers about formulas, inputs, examples, result copying, and private in-browser history.
What does the Statistics Calculator calculate?
It calculates count, sum, mean, median, mode, min, max, range, Q1, Q3, IQR, population variance, population standard deviation, sample variance, and sample standard deviation for one list of numbers.
What separators can I use?
You can separate values with commas, spaces, or line breaks. The calculator sorts the valid numbers before finding medians, modes, quartiles, and spread.
What do the main Statistics Calculator inputs mean?
The main inputs are the numbers, operation, mode, or known values the calculator needs. Keep units consistent, enter percentages the way the page label shows, and use the examples as a quick check before trusting the answer.
How should I read the Statistics Calculator answer?
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
Can I use decimals and negative numbers?
Yes. Decimal values and negative values work as long as each entry is a valid finite number.
How is the mean calculated?
The mean is the sum of all values divided by the count. The page also shows the sum and count so you can check the average.
How is the median calculated?
The data is sorted from smallest to largest. The median is the middle value, or the average of the two middle values when there is an even count.
Can a data set have no mode?
Yes. This calculator reports no mode when every value appears only once. If two or more values tie for the highest frequency, it reports each tied mode.
What is IQR?
IQR means interquartile range. It is Q3 minus Q1 and describes the spread of the middle half of the sorted data.
Does the calculator show sample and population standard deviation?
Yes. Population variance and standard deviation divide by the count. Sample variance and standard deviation divide by count minus 1, so sample results need at least two values.
Should I use sample or population spread?
Use population spread when the list is the whole group you care about. Use sample spread when the list is only part of a larger group, such as a survey, class sample, or experiment sample.
Why should I compare mean and median?
The mean uses every value, so a very high or low outlier can pull it. The median is often steadier when the data is skewed.
What should I check before copying the statistics?
Check that all values belong to one data set, the count matches what you expected, negative signs and decimals were pasted correctly, and your report uses the right rounding rule.
Can this calculator prove a research conclusion?
No. It summarizes the numbers you entered. It does not prove the data is representative, normally distributed, unbiased, or enough for a research conclusion by itself.
Is my statistics history private?
Yes. Recent statistics answers stay only in the current browser tab while you use the page. They are not sent to a server.