Statistics Calculator
Mean, median, mode, standard deviation and more
Paste or type a list of numbers, in any layout — commas, spaces or one per line — and this returns the full set of descriptive statistics at once: mean, median, mode, standard deviation, variance, quartiles, the interquartile range, and the minimum, maximum and range. It's built for the moment you have a column of figures and just want the summary without opening a spreadsheet.
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Mean, median, and knowing which to trust
The mean (the average everyone learns at school) and the median (the middle value when the numbers are lined up) usually sit close together, but when they don't, the gap is telling you something. A handful of very large or very small values drags the mean towards them while barely moving the median.
That's why average house prices and salaries are often quoted as medians: one billionaire on a street of ordinary earners would push the mean wildly upward and paint a misleading picture, whereas the median stays put and describes the typical case. Standard deviation, meanwhile, measures how spread out the numbers are — a small value means they cluster tightly around the mean, a large one means they're scattered. Read together, the three give you a fair sense of a dataset before you go any further.
❓ Frequently Asked Questions
What is the difference between mean, median, and mode? ▼
The mean is the average (sum ÷ count). The median is the middle value when data is sorted — better for skewed distributions. The mode is the value that appears most often. For example, in {1, 2, 2, 3, 10}: mean = 3.6, median = 2, mode = 2.
What is standard deviation? ▼
Standard deviation measures how spread out values are from the mean. A low SD means data points cluster tightly around the mean; a high SD means they are widely spread. The calculator shows both population SD (σ, when your data is the whole population) and sample SD (s, when it's a sample from a larger population).
When should I use sample vs population standard deviation? ▼
Use population standard deviation (σ) when your dataset contains every value in the group you're studying. Use sample standard deviation (s) — which uses n−1 in the denominator (Bessel's correction) — when your data is a sample taken from a larger population, which is most common in research.
What are quartiles and IQR? ▼
Quartiles divide sorted data into four equal parts. Q1 (the 25th percentile) is the median of the lower half; Q3 (75th percentile) is the median of the upper half. The IQR (Interquartile Range) = Q3 − Q1 and measures the spread of the middle 50% of data, making it robust to outliers.
How do I enter data into the statistics calculator? ▼
Paste your numbers separated by commas, spaces, or new lines — the calculator accepts all formats. For example: "12, 15, 18, 22, 9" or one number per line. Non-numeric values are automatically ignored.
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