Math & Statistics

What Is a Quartile?

Quartiles divide an ordered data set into four equal parts. The first quartile (Q1) is the 25th percentile, the second quartile (Q2) is the median, and the third quartile (Q3) is the 75th percentile. Together they describe the spread and center of the data.

Example

For 2, 4, 6, 8, 10, 12, 14, 16, the median is 9, Q1 is 5, and Q3 is 13 (using the median-of-halves method).

Methods

Several calculation methods exist, so software may give slightly different quartiles for small data sets.

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📊 Average Calculator (Mean, Median, Mode) Get the mean, median, mode, range, and sum of any list of numbers. Calculate → 📉 Standard Deviation Calculator Sample and population standard deviation and variance, with a step table. Calculate →

🔗 Related Terms

Percentile Median Interquartile Range (IQR) Outlier

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Last updated: September 29, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.