Statistics

Box Plot Calculator

Paste your data and instantly visualise the five-number summary, IQR, whiskers, and outliers — with a real box plot chart and plain-English interpretation of distribution shape.

Key statistics
IQR = Q3 − Q1
Lower fence = Q1 − 1.5 × IQR
Upper fence = Q3 + 1.5 × IQR
Skewness ≈ (Mean − Median) / σ

Enter your data

Paste numeric values separated by commas, spaces, or new lines. Minimum 4 values required.

Separate by commas, spaces, tabs, or new lines Enter at least 4 valid numeric values.
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Ready to calculate

Paste your data and press Calculate to see the five-number summary, IQR, outliers, and a real box plot chart.

Five-number summary
Min
Minimum
Q1
25th percentile
Median
50th percentile
Q3
75th percentile
Max
Maximum
IQR
Mean
Std dev
n
Outliers
Range
Distribution shape
Outliers detected (beyond 1.5 × IQR)
What this means

Box Plot
Median, quartiles, whiskers (1.5 × IQR), and outlier points
Interquartile range (IQR)
Median
Mean
Outlier
Frequency Distribution (Histogram)
Data grouped into bins — shows the overall shape and spread
Frequency
Mean
Median
How to Interpret and Improve Your Process
Practical guidance based on distribution shape, spread, and outliers
How it works

Reading a box plot

IQR

The box — middle 50%

The box spans from Q1 (25th percentile) to Q3 (75th percentile). This is the Interquartile Range (IQR) — the spread of the middle 50% of your data. A narrow box means data is concentrated. A wide box means high variability in the core of the dataset.

1.5×

Whiskers — the expected range

The whiskers extend to the most extreme values still within 1.5 × IQR of Q1 and Q3. Any data point beyond the whiskers is flagged as an outlier. Outliers are not errors by definition — they may represent real events worth investigating.

Skewness — distribution shape

If the median is near the centre of the box, the data is roughly symmetric. If it is closer to Q1, the distribution is right-skewed (long upper tail). Closer to Q3 means left-skewed. Comparing the mean and median also reveals skewness direction and magnitude.