📊 Statistics & Probability
Correlation Matrix Generator
Paste a CSV of numeric columns to get the Pearson correlation for every pair of columns in one matrix. Free, in-browser.
What This Calculator Tells You
A correlation matrix shows how strongly every pair of numeric columns in your data moves together. Each cell is a Pearson correlation coefficient from −1 to +1, so you can scan many relationships at once instead of testing them one pair at a time.
Paste a CSV with a header row and numeric columns. The tool calculates the full matrix in your browser.
What to Enter
- CSV: header row + numeric columns — first row holds the column names; every following row is one observation (a day, a customer, a store). All columns must be numeric, with commas between values. Keep column names short so the grid lines up.
Worked Examples
1. Marketing and operations data
Six weeks of ad spend, orders and average days to ship.
- Spend vs orders: +0.88 (strong positive).
- Orders vs days to ship: −0.99 — weeks with faster shipping had more orders.
- Spend vs days to ship: −0.86, likely an indirect link through orders rather than a direct effect.
2. Choosing model inputs
Before building a forecast, check whether two predictors are highly correlated with each other (above about 0.8). If so, keep one to avoid redundant inputs.
- The diagonal is always 1.00 because every column correlates perfectly with itself.
How to Read Your Result
- ±0.7 to ±1.0: strong relationship.
- ±0.3 to ±0.7: moderate.
- Below ±0.3: weak or none.
- Positive values move together; negative values move in opposite directions.
- The matrix is symmetric: the cell for A–B equals B–A.
Common Mistakes to Avoid
- Reading correlation as causation. Two columns can move together because of a third factor.
- Tiny samples. With 5–10 rows, strong-looking correlations often happen by chance.
- Non-numeric columns such as dates or names, which break the calculation — remove them first.
- Missing non-linear patterns. Pearson r measures straight-line relationships only.
When to Use This Calculator
- Explore which metrics move together in a business dashboard.
- Screen variables before regression or forecasting.
- Find redundant survey questions.
- Check data-science homework quickly.
Frequently Asked Questions
Does this draw a colored heatmap?
It produces the correlation matrix as a text grid. To color it, paste the values into a spreadsheet and apply conditional formatting with a red-to-green scale.
Which correlation method is used?
Pearson's correlation coefficient, the standard measure of linear relationship.
How many columns can I include?
Any number, but fewer than about 10 keeps the grid readable.
How do I test one pair in detail?
Use the correlation calculator for r and r² for a single pair.
Do you store the values I enter?
No. All calculations happen in your browser. Your data never leaves your device.
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