Dot Plot Maker
Type your data and get a dot plot — one dot or X per value, stacked over a number line — with the count at every value and the mean, median, mode and range worked out. Fractions such as 1/4 and 1 1/2 work too, for the line plots of measurement lessons. Free, no sign-up.
Separate values with commas, spaces or new lines. Fractions and mixed numbers work too — 3/4, 1 1/2 — but then separate values with commas or new lines, since a space joins a mixed number. Use semicolons if your numbers have decimal commas.
14 values
Counts
14
Values (n)
4.8571
Mean
5
Median
5
Mode
7
Range
| Value | Count |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 4 |
| 6 | 2 |
| 7 | 1 |
| 9 | 1 |
Labels and style
Takes the title out of the image and sets the figure number in bold and the title in italics above the chart — the APA 7 layout.
How to Use the Dot Plot Maker
- 1. Enter the values. Separate them with commas, spaces or new lines. For fractions and mixed numbers, write
3/4or1 1/2and separate the values with commas or new lines, since the space inside a mixed number joins it to its fraction. - 2. Choose dots or X marks. School line plots usually use X marks; statistics texts usually use dots. Either way, each value gets one mark, stacked above its place on the number line.
- 3. Group spread-out data. When most values occur only once, enter a bin width and the marks are stacked over equal-width bins instead of single values.
- 4. Read and export. The counts and the mean, median, mode and range appear under the plot. Add a title and a number-line title, switch on APA style if needed, and download the SVG or PNG.
What a Dot Plot Shows
A dot plot puts every observation on a number line, so the whole distribution is visible at once: where the values cluster, where there are gaps, and which values are unusual. It works best for small data sets — up to a few dozen values — with a limited number of distinct values, such as quiz scores out of 10 or the number of books each student read.
In the example, 14 students reported how many books they read over the summer: 2, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7 and 9. The tallest stack is at 5, with four dots, so the mode is 5. The median is the mean of the 7th and 8th values, (5 + 5) ÷ 2 = 5; the mean is 68 ÷ 14 ≈ 4.86; and the range is 9 − 2 = 7. The empty space at 8 and the lone dot at 9 stand out immediately — detail that a bar of means or even a box plot would hide.
Line Plots with Fractions
In elementary and middle school math, a line plot is a dot plot of measurements in fractions of a unit — pencil lengths to the nearest quarter inch, say. Enter the measurements as fractions and the number line is labeled in the same units. For ten pencils measuring 3 1/4, 3 1/2, 3 1/2, 3 3/4, 3 3/4, 3 3/4, 4, 4, 4 1/4 and 4 1/2 inches, the ticks fall at every quarter inch and the plot has one X above 3 1/4, two above 3 1/2, three above 3 3/4, two above 4 and one each above 4 1/4 and 4 1/2.
Questions about the data are then read off the plot. The difference between the longest and shortest pencil is 4 1/2 − 3 1/4 = 1 1/4 inches, which the tool reports as the range. The median is 3 3/4 inches, the mean of the 5th and 6th values, and the most common length — the mode — is also 3 3/4 inches.
Dot Plot, Histogram, Box Plot or Bar Graph?
| Data | Best chart | Why |
|---|---|---|
| A few dozen values, few distinct | Dot plot | Shows every value, its count, and the gaps |
| Hundreds of values, or a continuous measurement | Histogram | Bins keep the shape readable when single values rarely repeat |
| Several groups to compare | Box plot | Medians and spreads side by side in little space |
| Counts of categories (colors, majors) | Bar graph | Categories have no number line to stack along |
Common Dot Plot Mistakes
- Skipping empty values. The number line must be evenly spaced, with every value shown even when nothing sits above it — here, 8. Leaving it out would make 9 look like an ordinary neighbor of 7.
- Marks of different sizes or spacing. Readers compare the heights of the stacks, so every mark must be the same size and equally spaced. The tool fixes both.
- Too many values. With hundreds of values, or values that rarely repeat, the stacks become one-dot-high noise. Enter a bin width, or use a histogram.
- No title on the number line. Say what was measured and in what units: Pencil length (inches).
Frequently Asked Questions
- What is a dot plot in statistics?
- A dot plot is a graph that places one dot for every observation above its value on a number line, stacking the dots when values repeat. It shows the shape, center and spread of a small data set while keeping every individual value visible, which makes it a natural first graph for quiz scores, counts or measurements.
- What is the difference between a dot plot and a line plot?
- In school math they are usually the same graph: marks stacked above a number line, one per data value. Many curricula call it a line plot and draw X marks; statistics courses call it a dot plot and draw dots. Do not confuse either with a line graph, which joins points with lines to show change over time.
- How do you make a line plot with fractions?
- Write each measurement as a fraction or mixed number — 3/4, 2 1/2 — separated by commas or new lines. The tool finds the common denominator, labels the number line in those units (quarters, eighths and so on, up to sixteenths), and stacks one mark above each measurement. The range and median are shown as fractions too.
- How do you find the mean, median and mode from a dot plot?
- The mode is the value under the tallest stack. For the median, count the dots from the left until you reach the middle one — or the middle two, averaged. For the mean, multiply each value by the number of dots above it, add the products and divide by the total number of dots. The tool shows all three under the plot so you can check your working.
- What is a Wilkinson dot plot?
- Leland Wilkinson's dot plot (1999) stacks one dot per observation and groups nearby values into stacks so that dots never overlap, which lets it handle continuous data. Enter a bin width here for the fixed-width version of that idea: values are grouped into equal bins, each bin's dots are stacked over its center, and the table lists each bin's interval and count.
- When should I use a histogram instead of a dot plot?
- When there are more than a few dozen values, or when values rarely repeat — times, weights, incomes. Stacks of one or two dots then say little, while a histogram's bins show the shape. The Histogram Maker bins raw numbers by Sturges', Scott's or the Freedman–Diaconis rule.