How to
How to make a stem and leaf plot
A stem and leaf plot, or stemplot, splits every number into a stem and a one-digit leaf, then lists the leaves beside their stems. It reads like a histogram on its side, except that every original value can still be read back from it.
- Paste the numbers. Straight from a spreadsheet column, or typed with commas. They do not need to be sorted.
- Check the leaf unit. Automatic picks the last digit of your most precise value, and moves up a place if that would give more than 20 stems.
- Split crowded stems. If most values sit on two or three stems, use 2 or 5 lines per stem to see the shape.
- Compare two groups. Turn on Back to back; the first set's leaves grow to the left of the stem and the second set's to the right.
- Download. PNG or SVG with the key, or copy the plain text version from the summary.
Reading the key
The key tells you the place value of the leaf. With Key: 3 | 4 = 34, the stem is tens and the leaf is ones. With Key: 3 | 4 = 3.4, the stem is the whole number and the leaf is tenths. The same picture means very different numbers, so a stem and leaf plot without a key is incomplete.
Decimals, negatives and big numbers
Only one digit fits in a leaf, so digits smaller than the leaf unit are cut off by default, or rounded if you prefer; a note says how many values changed. Negative values get their own stems, including a -0 stem for negative values whose stem digit is zero, such as -3 when the leaf is the ones digit, so they are not mixed with small positive values. For three-digit data, a leaf unit of 10 keeps the plot compact.
Tip
Empty stems stay in the plot on purpose: they show gaps and outliers. For more than about a hundred values, a histogram or a box plot reads better, and small counts of whole numbers look good as a dot plot.
Questions people ask
How do I create a stem-and-leaf plot?
Sort the data, then split each number into a stem, every digit but the last, and a leaf, the last digit. Write the stems down the left in order, with no gaps, draw a line, and write each leaf beside its stem from smallest to largest. Add a key such as 4 | 7 = 47 so readers know the place value.
Can you skip stems in a stem-and-leaf plot?
No. Every stem between the smallest and largest value is listed, even when it has no leaves, because the empty rows are what show gaps and outliers. A plot that jumps from 6 straight to 12 hides the fact that nothing fell in between. This generator always writes the empty stems.
Can Excel create a stem-and-leaf plot?
Not directly. Excel has no stem and leaf chart type, so people build one with formulas: INT to get the stem, MOD or RIGHT to get the leaf, then TEXTJOIN to gather the leaves for each stem. Copying the column of numbers from Excel and pasting it here is quicker, and handles decimals and split stems for you.
What are the disadvantages of stem and leaf plots?
They suit small data sets, up to about a hundred values; beyond that the rows get too long to read. Values with many digits must be cut or rounded to one leaf digit, so some precision is lost. And the look depends on the leaf unit you choose, which is why the key and the leaf unit should always be shown.
Why do people use stem-and-leaf plots?
A stem and leaf plot shows the shape of the data like a histogram turned on its side, while keeping every actual value readable. You can find the minimum, maximum, median and mode straight from it, spot clusters, gaps and outliers, and compare two groups back to back, all from a quick sketch.