Correlation Coefficient Calculator (Pearson r)
Math ToolsPearson correlation between two lists of numbers
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All history →Correlation Coefficient Calculator (Pearson r) — at a glance
Measure how strongly two variables move together.
1, 2
2, 4
3, 5
Calculate r
r = 0.98
Strong positive
How to use it — step by step
One x, y pair per line.
1
Add your text
Paste or type your input into the box. The Sample button fills in an example.
2
Press Calculate r
The result is made instantly inside your browser.
3
Copy the result
Use the Copy button, or send it to another tool.
Pro tips
Small things that make the result better.
✦r runs from -1 to +1.
✦Correlation does not prove one thing causes the other.
✦Use at least five pairs.
Quick facts
Freeno signup
Privateruns in your browser
Instantresult in a second
No limituse it as often as you like
Frequently Asked Questions
What is a strong correlation?+
Values with an absolute r above about 0.7 are usually called strong.
Does it show cause?+
No. Two things can move together without one causing the other.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
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