Statistics Calculator
Calculate mean, median, mode, standard deviation, variance, quartiles, and more. Enter your numbers separated by commas, spaces, or new lines.
Enter numbers to calculate statistics.
Understanding the Results
Mean: The average—sum divided by count.
Median: The middle value when sorted.
Mode: Most frequently occurring value(s).
Variance: How spread out the data is (squared).
Standard Deviation: Square root of variance—same units as data.
IQR: Interquartile range (Q3 - Q1)—spread of middle 50%.
Frequently Asked Questions
When should I use mean vs median?
Use mean for normally distributed data. Use median when data has outliers (like income data where a few billionaires skew the average). Median is more robust to extreme values.
What does standard deviation tell me?
Standard deviation measures spread. For normal distributions, about 68% of data falls within 1 SD of the mean, 95% within 2 SD, and 99.7% within 3 SD. A small SD means data clusters tightly around the mean.
What are quartiles used for?
Quartiles divide data into four equal parts. They're used in box plots and to identify outliers. Values below Q1 - 1.5×IQR or above Q3 + 1.5×IQR are often considered outliers.