IQR Calculator (Interquartile Range) – Q1, Q3, Median & Interquartile Range

IQR (Interquartile Range) Calculator

Q1 (P25) • Q3 (P75) • Linear or nearest rank • value:count supported

Inputs

Numbers

Separators: comma, space, newline, semicolon. Frequency format: value:count, where count must be a positive integer.

Quartile method

Q1 is the 25th percentile and Q3 is the 75th percentile using the selected method.Different quartile conventions can produce slightly different Q1, Q3, and IQR values for the same dataset.

Options Show sorted preview

Large datasets are previewed in compressed form.

Action

Updating…

Use this IQR Calculator to find the first quartile (Q1), median, third quartile (Q3), and interquartile range of a numeric dataset.

Calculation Method

Q1 = 25th percentile

Median = 50th percentile

Q3 = 75th percentile

IQR = Q3 − Q1

The calculator supports both linear interpolation and nearest-rank quartile methods.

Example

For:

1, 2, 3, 4, 5, 6, 7, 8

Using the calculator’s linear interpolation method:

Q1 = 2.75

Q3 = 6.25

IQR = 6.25 − 2.75 = 3.5

Important Note

Quartile formulas vary between calculators and statistical software, so Q1, Q3, and IQR may differ slightly depending on the selected method. Use the same convention when comparing datasets.

Source

OpenStax Introductory Statistics 2e — Quartiles and Percentiles

More of our calculators...

Sample Size Calculator

Use our Sample Size Calculator to estimate sample size for a mean or proportion from confidence level, margin of error, and optional finite population correction.

Mean Median Mode Calculator

Use our Mean Median Mode Calculator to find the average, median, and mode from any data set. Supports raw numbers, value:count input, and sorted preview.

Chi-Square Calculator

Use our Chi-Square Calculator to run goodness-of-fit and independence tests, or find right-tail p-values and critical χ² values from df and alpha.

Confidence Interval Calculator

Use our Confidence Interval Calculator to find confidence intervals for a mean or proportion with standard error, critical value, margin of error, and lower and upper bounds.

Outlier Calculator (Tukey Fences)

Use our Outlier Calculator to find low and high outliers with Tukey fences and the IQR method. Get Q1, Q3, IQR, fences, counts, and sorted data fast.

t-test Calculator

Use our T-Test Calculator to compute t statistic, p-value, confidence interval, and conclusion for one-sample, Welch, pooled, or paired t-tests.

p-value Calculator

Use our P-value Calculator to calculate one-tailed or two-tailed p-values for Z, t, chi-square, and F test statistics.

Margin of Error Calculator

Use our Margin of Error Calculator to find margin of error for a mean or proportion from sample size, confidence level, and z value.

Standard Deviation Calculator

Use our Standard Deviation Calculator to find sample or population standard deviation from a data set. Get variance, mean, range, and sorted values fast.