Calculadora de Quartis
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
Q1=25%, Q2=50%, Q3=75%
About this calculator
The Quartile Calculator is a statistical tool that computes the three quartiles (Q1, Q2, Q3) of a data set. Quartiles divide ordered data into four equal parts: Q1 is the 25th percentile, Q2 the median (50th percentile), and Q3 the 75th percentile. This calculator helps understand data spread and symmetry, especially in exploratory analysis.
Calculation involves sorting values in ascending order. Quartile positions are determined: Q1 at 0.25*(n+1), Q2 at 0.50*(n+1), Q3 at 0.75*(n+1), where n is the number of observations. If the position is not an integer, linear interpolation between adjacent values is used. For example, with 9 values, Q1 is at position 2.5, averaging the 2nd and 3rd values.
When to use? Ideal for statistics teachers and students needing quick quartile calculations, data analysts summarizing sample distributions, or quality control professionals assessing process variability. Also useful for comparing distributions between groups, such as class scores.
Cautions: The calculator assumes numeric data with no missing values. For datasets with many repeated values, quartiles may coincide with those values. Different quartile calculation methods (exclusive vs. inclusive) may yield slightly different results; this calculator uses the standard Tukey method.
Frequently asked questions
What do Q1, Q2, and Q3 mean?
Q1 is the first quartile (25% of data below it), Q2 is the median (50% below), and Q3 is the third quartile (75% below).
How does the calculator handle repeated numbers?
The calculator sorts the data and interpolates when needed. Repeated values are treated normally, and quartiles may coincide with those values.
Can I use it for any number of values?
Yes, it works for any numeric dataset with at least 1 value. For fewer than 3 values, quartiles may be equal.
Which calculation method is used?
We use Tukey's method (inclusive) for quartile positions, with linear interpolation when necessary.
Does the result change if I input numbers in a different order?
No, the calculator automatically sorts the data, so input order does not affect the result.