Box Plot Maker

How to make a box plot

1. Paste your numbers into the box. Any mix of spaces, commas and new lines works. For several groups, copy the columns from a spreadsheet with their header row: each column becomes a box named from its header.
2. Only have the summary? Tap 5-number summary and type minimum, Q1, median, Q3 and maximum, one group per line.
3. Pick the quartile method your class, calculator or spreadsheet uses (the four are explained below).
4. Read The steps: sorted data, n, minimum, Q1, median, Q3, maximum, IQR, the fences and the outliers, each with the values it used. Tap Copy steps as text to paste them into homework or a report.
5. Choose horizontal or vertical, whiskers and the mean marker, then download a PNG (1x to 4x) or an SVG, or make a share link.

The four quartile methods

The minimum, maximum and median are the same in every method. Q1 and Q3 are not, because there is more than one accepted way to find a quarter of the way through a list. Each sentence below is written from the method's own documentation, fetched on 2026-10-19.

• Median of halves, median excluded. Split the sorted data at the median; with an odd count the median itself goes in neither half; Q1 and Q3 are the medians of the lower and upper halves (the rule TI-83 calculators use for box plots and 1-Var Stats). Source: en.wikipedia.org/wiki/Quartile, Method 1, fetched 2026-10-19.
• Median of halves, median included. Split the sorted data at the median; with an odd count the median goes in both halves; Q1 and Q3 are the medians of the halves (also called Tukey's hinges). Source: en.wikipedia.org/wiki/Quartile, Method 2, fetched 2026-10-19.
• Inclusive, QUARTILE.INC. Excel describes QUARTILE.INC as returning “the quartile of a data set, based on percentile values from 0..1, inclusive”: Q1 sits at rank (n − 1) × 0.25 + 1 in the sorted data, Q3 at (n − 1) × 0.75 + 1, interpolating between neighbours. Excel's older QUARTILE and Google Sheets' QUARTILE give the same numbers. Source: Microsoft Support, QUARTILE.INC function, fetched 2026-10-19.
• Exclusive, QUARTILE.EXC. Excel describes QUARTILE.EXC as returning “the quartile of the data set, based on percentile values from 0 to 1, exclusive”: Q1 sits at rank (n + 1) × 0.25, Q3 at (n + 1) × 0.75, interpolating, and it needs at least 3 values. Source: Microsoft Support, QUARTILE.EXC function, fetched 2026-10-19.

A worked example

Take 1 2 3 4 5 6 7 8 9. The median is the 5th value, 5. With the median excluded, the lower half is 1 2 3 4, so Q1 = (2 + 3) / 2 = 2.5, and Q3 = (7 + 8) / 2 = 7.5. With it included, the lower half is 1 2 3 4 5 and Q1 = 3, Q3 = 7. QUARTILE.INC puts Q1 at rank (9 − 1) × 0.25 + 1 = 3, the value 3, and Q3 at rank 7, the value 7. QUARTILE.EXC puts Q1 at rank (9 + 1) × 0.25 = 2.5, halfway between 2 and 3, so 2.5, and Q3 at rank 7.5, so 7.5. Same data, two different boxes, which is why your answer may not match a friend's spreadsheet.

Now outliers. For 2 4 4 5 6 7 8 30 (textbook method), Q1 = 4 and Q3 = 7.5, so IQR = 3.5 and 1.5 × IQR = 5.25. The fences are 4 − 5.25 = −1.25 and 7.5 + 5.25 = 12.75. 30 is above 12.75, so it is drawn as a dot, and the upper whisker stops at 8, the largest value inside the fence.

What it cannot do

• A five-number summary cannot show outliers: it does not say which values lie beyond the fences, so the whiskers run to the minimum and maximum. The steps still say whether at least one outlier must exist.
• It runs no hypothesis tests and gives no p-values or confidence intervals; it describes the data you give it.
• More than 100,000 values is slow to redraw, and the page says so when you pass it.
• Outliers use the 1.5 × IQR rule only; there is no option for 3 × IQR, standard deviations or other rules.
• Columns need a header row (or tabs between them, as a spreadsheet copies); several comma-separated lines without a header are read as one list. Up to 12 groups.
• Share links longer than 2,000 characters may be cut short by some chat apps; send the PNG or SVG instead.
• The PNG and SVG use the fonts on the device that opens them (Geist where it is installed, otherwise Helvetica or Arial).

Privacy and what is stored

Your numbers never leave your device: everything is worked out and drawn by code in this page and exports are made in the browser. The latest data and settings are saved in this browser's local storage once you edit them, so a reload keeps them; Clear saved plot deletes them in one tap. The page sends an anonymous page-view count and, at most, two fixed words (boxplot-make, boxplot-export), never a number or a name. A share link carries the data after the #, which browsers do not send to any server, and opening one saves nothing unless you tap Keep this copy.

Questions

How do I make a box plot from a five-number summary?

Tap 5-number summary and type the minimum, Q1, median, Q3 and maximum on one line, for example 10 20 25 30 50, or Class A: 10 20 25 30 50 to name it. One line per group draws several boxes on one scale. The whiskers run from the minimum to the maximum, because a summary cannot say which values, if any, are outliers; the steps tell you whether the minimum or maximum lies outside the 1.5 × IQR fences, which means at least one outlier exists.

How do I make a box plot with outliers?

Paste the raw numbers. The page works out IQR = Q3 − Q1, the lower fence Q1 − 1.5 × IQR and the upper fence Q3 + 1.5 × IQR; any value outside the fences is drawn as a dot and listed in the steps, and each whisker stops at the furthest value still inside its fence. For 2 4 4 5 6 7 8 30 the fences are −1.25 and 12.75, so 30 is an outlier and the upper whisker ends at 8.

Why does Excel or Google Sheets give different quartiles from my textbook?

They use different rules. Most textbooks and TI calculators take the median of each half, leaving the middle value out when the count is odd; Excel's QUARTILE and QUARTILE.INC and Google Sheets' QUARTILE interpolate at rank (n − 1) × p + 1, and QUARTILE.EXC at rank (n + 1) × p. For 1 to 9 the textbook rule gives Q1 2.5 and Q3 7.5, the inclusive rule 3 and 7, the exclusive rule 2.5 and 7.5. Pick the method that matches your class or your spreadsheet and the steps show the working.

Can I make several box plots side by side?

Yes. Copy two or more columns from a spreadsheet with their header row and paste them: each column becomes its own box, named from its header, all on one shared scale. Switch Layout to vertical for boxes standing side by side.

Is this box plot maker free, and is my data uploaded?

It is free, with no account, no watermark and no ads. The numbers are worked out and drawn by code in this page on your own device and nothing you paste is uploaded. The last plot is kept in this browser so a reload does not lose it, and one tap clears it.