Correlation Calculator

Pearson correlation coefficient between two data sets.

Correlation (r)
0.852803

strong positive relationship

0.727273
Strength
strong
Pairs used
5
Show the working
  1. 1Pearson r = covariance ÷ (σx × σy) = 0.852803
  2. 2r² = 0.7273 — the share of variance explained
Formula
r = Σ(x−x̄)(y−ȳ) ÷ √(Σ(x−x̄)²·Σ(y−ȳ)²)

How it works

Pearson's r measures how strongly two variables move together, from −1 (opposite) through 0 (none) to +1 (identical).

Example

The X/Y pairs above have r ≈ 0.83 — a strong positive correlation.

About the Correlation Calculator

Pearson correlation coefficient between two data sets. It sits in the Statistics section of NWS Calc, a free collection of calculators that run entirely in your browser. There is no signup, no paywall and no tracking — open the page, enter your numbers, get an answer.

Frequently asked questions

Is the Correlation Calculator free to use?
Yes. Every calculator on NWS Calc is completely free, with no signup, no usage limits and no ads.
Does my data leave my device?
No. The Correlation Calculator runs entirely in your browser using JavaScript. Nothing you type is uploaded, logged or stored on a server.
Can I use the Correlation Calculator on my phone?
Yes. The page is fully responsive and works in any modern mobile or desktop browser — there is nothing to install.
What else is in Statistics?
Mean, deviation, regression, probability and distributions. You can browse the full Statistics category for related calculators.

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