Correlation Coefficient Calculator
Measure the strength and direction of relationships between variables. Choose Pearson for linear relationships, Spearman or Kendall for ranks and monotonic trends.
Updated · By Bibin XavierData 90 × 12
| IDtext · 90 levels | Grouptext · 3 levels | Gendertext · 2 levels | Agenumeric | Hours_Studynumeric | Anxietynumeric | Motivationnumeric | Pre_Scorenumeric | Post_Scorenumeric | Exam_Scorenumeric | Passednumeric · coded | Satisfactionnumeric · coded |
|---|---|---|---|---|---|---|---|---|---|---|---|
| S001 | Control | Male | 23 | 11.2 | 29 | 4.6 | 60 | 62 | 67 | 1 | 2 |
| S002 | Workshop | Female | 23 | 3.9 | 28 | 3.5 | 54 | 70 | 54 | 0 | 2 |
| S003 | Online | Female | 18 | 10.1 | 32 | 4 | 55 | 57 | 66 | 0 | 3 |
| S004 | Control | Male | 26 | 13.6 | 41 | 3.5 | 52 | 55 | 59 | 0 | 3 |
| S005 | Workshop | Female | 22 | 9.7 | 27 | 3.6 | 56 | 63 | 65 | 0 | 4 |
| S006 | Online | Female | 20 | 7.9 | 32 | 3.8 | 65 | 82 | 65 | 0 | 2 |
| S007 | Control | Female | 20 | 6.3 | 28 | 3 | 72 | 83 | 61 | 0 | 3 |
| S008 | Workshop | Male | 22 | 8 | 29 | 3.1 | 64 | 72 | 62 | 1 | 3 |
Variables and options
Results
90 rows · example dataCorrelation matrix (r)
| Variable | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| 1. Exam_Score | — | |||
| 2. Hours_Study | .36*** | — | ||
| 3. Motivation | .40*** | .65*** | — | |
| 4. Anxiety | -.35*** | .20 | .04 | — |
Note. * p < .05. ** p < .01. *** p < .001. Pairwise deletion of missing values.
Pairwise details
| Pair | n | r | 95% CI | t | p | Strength |
|---|---|---|---|---|---|---|
| Exam_Score – Hours_Study | 90 | .362 | [.167, .529] | 3.64 | < .001 | moderate |
| Exam_Score – Motivation | 90 | .398 | [.209, .559] | 4.07 | < .001 | moderate |
| Exam_Score – Anxiety | 90 | -.348 | [-.518, -.152] | -3.48 | < .001 | moderate |
| Hours_Study – Motivation | 90 | .650 | [.511, .755] | 8.02 | < .001 | strong |
| Hours_Study – Anxiety | 90 | .201 | [-.007, .391] | 1.92 | .058 | weak |
| Motivation – Anxiety | 90 | .041 | [-.168, .246] | 0.38 | .704 | negligible |
Note. Confidence intervals use the Fisher z transform.
Hours_Study by Exam_Score
Interpretation
Exam_Score and Hours_Study show a moderate positive correlation (r = .36), which is statistically significant. Higher values of one tend to go with higher values of the other. Correlation does not establish cause.
How to cite this tool
Using these results in a thesis, journal article, report or class assignment? Please cite this free tool so others can find it. It keeps the site free.
APA 7
Xavier, B. (2026). Correlation Coefficient Calculator [Web application]. FreeStatisticalTools.com. https://freestatisticaltools.com/correlation-calculator/
BibTeX
@software{xavier_correlation_2026,
author = {Xavier, Bibin},
title = {Correlation Coefficient Calculator},
publisher = {FreeStatisticalTools.com},
year = {2026},
url = {https://freestatisticaltools.com/correlation-calculator/},
note = {Web application}
}Suggested sentence for your methods section: “The analysis was carried out with the free Correlation Coefficient Calculator tool on FreeStatisticalTools.com (Xavier, 2026).”
What is a correlation coefficient?
A correlation coefficient measures the strength and direction of the relationship between two variables. This calculator builds a full correlation matrix with significance stars and gives the confidence interval and test for every pair.
When to use a correlation coefficient
Use Pearson’s r for two continuous, roughly normal variables with a linear relationship. Use Spearman’s ρ or Kendall’s τ for ordinal data, outliers or curved but monotonic trends. A point-biserial correlation is Pearson’s r with one variable coded 0/1.
Assumptions
- Pearson: linearity, no extreme outliers, approximate bivariate normality.
- Spearman and Kendall: a monotonic relationship.
How to use this tool
- Enter your data. Paste columns from Excel, Google Sheets or SPSS with variable names in the first row, or upload a CSV or Excel file. The example data shows the expected layout.
- Choose the variables. Select the variables.
- Set the options. Fill in coefficient.
- Read the results. Results update automatically. Read the plain-English interpretation, then use Copy table to paste APA-style tables into Word and Copy for the results sentence.
How to report a correlation coefficient in APA style
“Study hours were positively correlated with exam scores, r(88) = .47, p < .001.”
Frequently asked questions
Pearson or Spearman correlation?
Use Pearson’s r for continuous variables with a linear relationship and no extreme outliers. Use Spearman’s ρ for ordinal data, outliers or monotonic but curved relationships.
How do I interpret r?
By Cohen’s guidelines, |r| = .10 is weak, .30 moderate and .50 strong. The sign shows the direction of the relationship.
How do I calculate a point-biserial correlation?
Code the binary variable as 0 and 1 and run Pearson’s r; the result is the point-biserial correlation.
Related tools
Browse all categories
Data cleaning and preparation · Describe and explore · Compare means · Nonparametric tests · Correlation and regression · Bayesian statistics · Categorical data · Reliability and agreement · Multivariate analysis · Structural equation modeling · Econometrics and time series · Panel data and causal inference · Marketing and decision research · Survival, clinical and meta-analysis · Study planning and calculators · PLS-SEM