Formula Used
The calculator first sorts all entered values from lowest to highest.
It then finds the median, first quartile, and third quartile.
The interquartile range is calculated as:
IQR = Q3 - Q1
The lower and upper fences are:
Lower Fence = Q1 - k × IQR
Upper Fence = Q3 + k × IQR
The value k is the fence multiplier.
A common value is 1.5.
Values below the lower fence or above the upper fence are marked as outliers.
The whiskers stop at the smallest and largest non-outlier values.
How To Use This Calculator
Enter your dataset in the data box.
Separate values with commas, spaces, or semicolons.
Choose the quartile method.
Keep the fence multiplier at 1.5 for standard outlier checks.
Press the calculate button.
The result appears below the header and above the form.
Review the five-number summary, fences, whiskers, and outlier list.
Use the CSV or PDF buttons to save the result.
Box Plot On Calculator Guide
What This Tool Does
A box plot is a compact way to study spread.
It shows the center, range, and unusual values.
This calculator turns raw numbers into a clear summary.
It is useful for school, business, quality control, and general data review.
You can paste values from a sheet or type them by hand.
The tool sorts the data before making any calculation.
This avoids mistakes caused by unordered entries.
Why Quartiles Matter
Quartiles divide ordered data into useful sections.
Q1 marks the lower quarter.
The median marks the middle.
Q3 marks the upper quarter.
The box runs from Q1 to Q3.
That box contains the middle half of the data.
A short box means values are close together.
A long box means values are more spread out.
Understanding Whiskers
Whiskers show the non-outlier spread.
They do not always equal the minimum and maximum.
The calculator checks fences first.
Any value outside the fences is listed as an outlier.
Then the whiskers stop at valid data points.
This makes the chart more honest.
Extreme values are still shown separately.
Outlier Checking
Outliers can reveal errors or special cases.
They can also show real events.
For example, one delivery may take much longer.
One score may be much lower.
The calculator uses the IQR rule.
This rule is common because it is simple.
It does not rely on averages.
That helps when data is skewed.
Best Practice
Use at least five values.
More values give a better picture.
Check your units before entering data.
Do not mix minutes with hours.
Do not mix dollars with cents.
Compare similar datasets only.
Save your result when you need records.
The export buttons help with reports and assignments.
FAQs
What is a box plot?
A box plot is a chart that shows quartiles, median, whiskers, and possible outliers. It helps you understand data spread quickly.
How many values should I enter?
You should enter at least five values. Larger datasets usually create more reliable quartiles and better outlier detection.
What does Q1 mean?
Q1 is the first quartile. It marks the point where about 25 percent of sorted values are below it.
What does Q3 mean?
Q3 is the third quartile. It marks the point where about 75 percent of sorted values are below it.
What is IQR?
IQR means interquartile range. It equals Q3 minus Q1 and measures the spread of the middle half of data.
How are outliers detected?
The calculator uses fences. Values below Q1 minus k times IQR or above Q3 plus k times IQR are outliers.
What fence multiplier should I use?
The standard value is 1.5. You may increase it for a looser check or reduce it for stricter screening.
Can I download the result?
Yes. Use the CSV button for spreadsheet work. Use the PDF button for printable summaries and reports.