A stem and leaf plot is a table that splits each number into two parts: a stem (the leading digit or digits) and a leaf (the last digit). It preserves every original value while showing the shape of the distribution.
To build one from your own values, open the free stem and leaf plot maker. For larger datasets where individual values matter less, use the histogram maker.
The core idea
Take a set of numbers, say test scores from 62 to 98. Group them by tens digit: 60s, 70s, 80s, 90s. These groups are the stems. Write the stems in a column. For each score, write the ones digit next to its stem. These are the leaves.
The result is a compact table that functions like a histogram but shows each actual value:
6 | 2 7 9
7 | 1 4 4 8
8 | 0 2 5 5 5 9
9 | 1 3 8
Read left to right: 6|2 means 62; 8|5 means 85. You can read back every original number.
Stems and leaves explained
- Stem — the leading portion of a number. For two-digit numbers it's the tens digit; for three-digit numbers it's the hundreds (or hundreds + tens). Written once per row and shared by all leaves in that row.
- Leaf — the final digit of each number. Written individually, one per data point. Multiple leaves on the same stem show how many values fall in that range.
- Key — a small note explaining the scale, e.g. "4 | 7 means 47." Always include it — stems can represent different magnitudes depending on the data.
Split-stem plots
When data clusters in a narrow range, a standard plot has too few stems and each row becomes crowded with leaves. A split-stem plot divides each stem into two rows:
- First row: leaves 0–4
- Second row: leaves 5–9
This doubles the number of rows and spreads the data out for a clearer shape. You'll often see this in statistics textbooks for datasets that span just one or two decades.
Back-to-back stem and leaf plots
A back-to-back (or two-sided) plot compares two groups using a shared set of stems in the center:
Group A Stem Group B
9 8 2 | 7 | 1 5
7 5 4 1 | 8 | 0 2 6 9
3 0 | 9 | 4 7
Group A's leaves read right-to-left; Group B's read left-to-right. This is the standard format for comparing two distributions (male vs female, before vs after) when the dataset is small enough to show individual values.
Stem and leaf plot vs histogram
| Stem and leaf plot | Histogram | |
|---|---|---|
| Preserves original values | Yes | No (bins aggregate) |
| Good for small datasets (n < 50) | Yes | Not ideal |
| Good for large datasets (n > 100) | Cluttered | Yes |
| Works without software | Yes (can do by hand) | No |
| Shows distribution shape | Yes | Yes |
For small datasets where showing every value matters — especially in classrooms and introductory statistics — stem and leaf plots are unmatched. For large datasets, use a histogram.
When to use a stem and leaf plot
- Classroom statistics: test scores, survey results, measurement data
- Small datasets (10–50 values) where individual values matter
- Comparing two groups side-by-side with a back-to-back plot
- When you need to show both the distribution shape and the actual numbers
FAQ
What is the leaf unit in a stem and leaf plot?
The leaf unit specifies what the last digit represents. If the data is in whole numbers (72, 85), the leaf unit is 1 (ones digit). If data is in tens (720, 850), the leaf unit is 10. The key printed below the plot always specifies this: "5 | 3 means 53" or "5 | 3 means 530."
Can a stem and leaf plot have decimals?
Yes. For data like 4.2 and 5.7, the stem is the units digit and the leaf is the decimal. The key would read "4 | 2 means 4.2." Some plots extend to two decimal places by using the first decimal digit as the stem and the second as the leaf.
Why do leaves in a back-to-back plot read right-to-left on one side?
The stems are in the center column, so the left group's leaves grow outward to the left — the rightmost leaf is the smallest digit, and leaves increase as you read away from the stem. This is convention, not a rule. Some software reverses this; always check the key.
How this guide is reviewed
This guide is maintained by the ChartsMakers Editorial Team and reviewed for statistical accuracy, product behavior, and clarity. When a guide relies on software behavior or statistical definitions, we check it against official documentation or established references. See our editorial policy.