About PicoStat

PicoStat is an independent, advertising-supported site for anyone who has ever had a column of numbers and no quick way to make sense of it — students checking homework, analysts sanity-checking a figure, or the merely curious. Short version below.

The tools

Six free calculators, no account, nothing to install: Mean, Median & Mode, Standard Deviation, Z-Score, Sample Size, Correlation, and a Data Size Converter.

How they work

Every one runs entirely in your browser using the standard textbook definitions — the arithmetic mean and the middle-and-most-frequent values; the population/sample standard deviation from the squared deviations; the z-score as (value − mean) ÷ standard deviation; sample size from your confidence level, margin of error, and population; the Pearson correlation coefficient between two paired columns; and byte-unit conversion across the binary (KiB/MiB) and decimal (KB/MB) scales. Nothing you paste in is uploaded or stored.

Where the numbers come from

The formulas are the common, widely taught ones — not a private method we invented. Each tool’s own page shows the formula it uses so you can check the working rather than trust a black box.

The museum

For a change of pace, the noindexed Measurement & Data Museum is an illustrated wander through the history of counting, measuring, and making sense of data. There are also longer explainers in the journal and the Learn hub.

Straight talk about ads & advice

The site is kept free by advertising. The calculators give correct arithmetic for the inputs you give them, but a correct statistic is not the same as a correct conclusion — interpreting a result is on you (or a qualified statistician). PicoStat is not affiliated with any software vendor, journal, or standards body.

Questions?

Spotted a wrong result or want a calculator that isn’t here? Get in touch— that feedback is how the site improves.