Statistics

Correlation Coefficient Calculator

Enter paired values: the first X goes with the first Y, and so on. The result runs from −1 (perfect negative relationship) through 0 (none) to 1 (perfect positive).

For example: hours studied.

For example: test score.

Your result will appear here.

How it's calculated

Pearson's r is the covariance of X and Y divided by the product of their standard deviations. Squaring it gives R², the share of the variation in Y that a straight line through X explains.

Correlation doesn't show cause. Two things can move together because a third thing drives both.

r = Σ(x − x̄)(y − ȳ) ÷ √(Σ(x − x̄)² × Σ(y − ȳ)²)

How to do it in Excel

=CORREL(A2:A9, B2:B9)
Pearson's r. PEARSON returns the same value.
=RSQ(B2:B9, A2:A9)
R squared.
=SLOPE(B2:B9, A2:A9)
Slope of the line of best fit. INTERCEPT gives the other half.