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Quartile Calculator

Find the minimum, lower quartile, median, upper quartile and maximum of your data, with the interquartile range and any outliers.

Rules last checked 25 October 2026Every step shown

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Median (Q2)

40

Lower quartile (Q1)
15
Upper quartile (Q3)
43
Interquartile range
28
Minimum and maximum
6 to 49
Outliers
None

Five-number summary: 6, 15, 40, 43, 49. The middle half spans 28.

How it's worked out

  1. Sort11 values
  2. QuartilesQ1 and Q3 are the medians of the lower and upper halves15, 40, 43
  3. Outlier fencesQ1 − 1.5 × IQR and Q3 + 1.5 × IQR-27 and 85
  • Software such as Excel can use a different quartile method and give slightly different Q1 and Q3.

How it works

IQR = Q3 − Q1 · Outliers: below Q1 − 1.5 IQR or above Q3 + 1.5 IQR

Worked example

For 6, 7, 15, 36, 39, 40, 41, 42, 43, 47, 49: the median is 40, Q1 is 15 and Q3 is 43, so the IQR is 28 and there are no outliers.

Questions people ask

How do I find quartiles?

Sort the data and find the median. Q1 is the median of the lower half and Q3 the median of the upper half.

What is the interquartile range?

Q3 minus Q1: the spread of the middle half of the data.

What counts as an outlier?

A value more than 1.5 × IQR below Q1 or above Q3.

Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem