Calculators
Interquartile Range Calculator
Calculate interquartile range, first quartile, median and third quartile for signed numbers privately in your browser.
Measure the spread of the middle half of your data.
Sort the values, split them into two halves, and find the median of each half. For odd counts, exclude the overall median from both halves. Q1 is the lower-half median and Q3 is the upper-half median; IQR = Q3 − Q1. For 1, 2, 3, 4, 5, 6, and 7, Q1 = 2, median = 4, Q3 = 6, and IQR = 4. Even-sized medians average their two middle values. Quartile conventions differ: software using interpolated percentiles may return different answers. This tool consistently uses the median-of-halves method with at least two values. Identical values have zero IQR. Enter up to 10000 finite signed numbers separated by spaces, commas, semicolons or newlines; scientific notation is supported but thousands separators are not. Use consistent units; IQR shares those units. Results use browser floating-point arithmetic and display up to 12 significant digits. All processing stays in your browser.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
How is interquartile range calculated?
IQR = Q3 − Q1. Sort the data and find the medians of its lower and upper halves. Exclude the overall median when the dataset has an odd count. For 1 through 7, Q1 = 2, Q3 = 6 and IQR = 4.
Why might another calculator give different quartiles?
Quartile conventions vary, especially for small datasets. This calculator uses the median-of-halves method and excludes the overall median for odd counts. It does not use interpolated percentile formulas.
Which values are accepted?
Enter 2 to 10000 finite numbers, including negatives and zero. Separate them with spaces, commas, semicolons or newlines. Scientific notation is supported. Use decimal points and omit thousands separators.
What does a zero IQR mean?
Q1 and Q3 are equal, so the middle half has no spread under this quartile convention. Some values outside that interval may still differ.
Is my data uploaded?
No. Calculations and copying run in your browser. Results are displayed to 12 significant digits; reset clears the input and result.