About the Stem and Leaf Plot Generator
This stem and leaf plot generator turns a list of numbers into a tidy stem-and-leaf display. Each value is split into a stem (the leading digits) and a leaf (the next digit), stems are listed in order down the left, and the leaves for each stem are sorted along the right. The result keeps every original value visible while showing the shape of the distribution like a sideways histogram.
Teachers and students use stem-and-leaf plots in middle-school, high-school and introductory statistics classes to find the median, mode, range and clusters by hand, and analysts use them for a quick look at small data sets. The generator picks a sensible stem unit automatically based on the spread and precision of your data, or you can force a stem unit and split each stem into two rows (leaves 0–4 and 5–9) to spread out crowded data.
Leaves are formed by truncating, as in Tukey’s original method: with a leaf unit of 1, the value 47.8 is shown as 4 | 7. Negative numbers get negative stems, including a separate −0 stem for negative values whose stem digit is zero (for example −4 with a stem unit of 10). Empty stems inside the range are kept so gaps in the data stay visible.
How to use the stem and leaf plot generator
- 1Paste or type your numbers into the data box, separated by commas, spaces or new lines.
- 2Leave the stem unit on Automatic, or pick one to control which digit becomes the leaf.
- 3Turn on split stems if most leaves pile up on just a few stems.
- 4Read the plot top to bottom, using the key to translate stem | leaf back into a value.
- 5Use the median, range and frequency table to describe the distribution.
Formula and method
Each value is divided by the leaf unit and truncated to a whole number m. The last digit of m is the leaf and the remaining digits are the stem. With a stem unit of 10 (leaf unit 1), 47 becomes stem 4 and leaf 7; with a stem unit of 1 (leaf unit 0.1), 4.7 becomes the same 4 | 7, which is why every plot needs a key.
In automatic mode the generator starts from the finest leaf unit your data use (for example 0.1 if any value has one decimal) and increases the stem unit by factors of 10 until the plot has at most 20 stems (40 rows when stems are split). Split stems put leaves 0–4 on the first row and 5–9 on the second. Every stem between the minimum and maximum is listed, even if it has no leaves, so the shape of the distribution is preserved.
- x
- A data value
- stem unit
- Place value represented by one step of the stem (e.g. 10)
- leaf unit
- Place value of the leaf digit (stem unit ÷ 10)
- m
- Value expressed as a whole number of leaf units (truncated)
Worked examples
Test scores out of 100 (23 students)
The scores run from 42 to 93, so tens digits make natural stems (4 to 9) and ones digits become leaves. The 60s row is longest with eight leaves, and the 12th of 23 sorted values — the median — is 64, which also appears three times as the mode. The range is 93 − 42 = 51.
Decimal data with split stems
With one decimal place the leaf unit is 0.1, so 3.4 is stem 3, leaf 4. Splitting each stem puts leaves 0–4 on the first row and 5–9 on the second, giving six rows that show the cluster around 3.1–3.4 more clearly than three crowded rows would.
Three-digit values with automatic stem unit
Values from 112 to 188 with a stem unit of 10 need only eight stems (11 to 18), so the generator keeps the ones digit as the leaf and no information is lost. The key 18 | 8 = 188 shows how to read each row; the middle (6th) value is 149.
Frequently asked questions
How do you read a stem and leaf plot?+
Combine each stem with each of its leaves using the key. If the key says 4 | 7 = 47, then the row 4 | 2 5 7 holds the values 42, 45 and 47. The number of leaves on a row is the frequency for that interval.
How do you find the median from a stem and leaf plot?+
Count the leaves to get n, then count through the plot from the top to the middle value (position (n + 1) ÷ 2). For an even n, average the two middle values. The calculator also reports the median directly.
What is a split stem and leaf plot?+
A split stem plot uses two rows per stem: the first holds leaves 0 to 4 and the second holds leaves 5 to 9. It is useful when the data span only a few stems, because it doubles the number of rows and reveals more of the distribution’s shape.
How do you handle decimals?+
Choose the stem unit so the leaf is the last digit you care about. For data like 3.4 and 4.5 use a stem unit of 1, so the ones digit is the stem and the tenths digit is the leaf. Any further digits are truncated, which the key makes clear.
How are negative numbers shown?+
Negative values get negative stems, such as −2 | 5 for −25. Values between −9 and 0 use a separate −0 stem so they are not mixed with values from 0 to 9. Negative rows appear above the positive ones, from most negative to least.
Stem and leaf plot vs histogram: which is better?+
A stem and leaf plot keeps every individual value, which makes it ideal for small data sets (roughly 15 to 150 values) and for finding the median or mode by hand. Histograms scale better to large data sets and allow any bin width.