Drop a CSV, pick two columns, and get the correlation coefficient — plus a plain-English reading of what it means. Runs entirely in your browser: no upload, no sign-up, your data never leaves your device.
The correlation coefficient (Pearson’s r) measures how strongly two numeric columns move together, on a scale from −1 to +1. A value near +1 means they rise together; near −1 means one rises as the other falls; near 0 means there’s no linear relationship. It’s unitless — it doesn’t depend on the scale of your columns.
Correlation isn’t causation — two columns can move together because a third thing drives both. Pearson’s r only sees linear relationships and is sensitive to outliers. For a non-linear or rank relationship, use Spearman instead. Want the whole correlation matrix or to ask a follow-up in plain English? Open the full workbench →