Cronbach alpha calculator
Each field is one item and successive numbers are responses from the same people. Complete at least two fields.
Scale items
| Item | n | Mean | Variance |
|---|---|---|---|
| Fill in the fields above — the result is computed on this page. | |||
How do I use this page?
- Paste each item in a separate field.
- Check matching respondent order.
- Read alpha and item variances.
What this page does not do: Reverse-worded items must be recoded first. Missing responses or unequal field lengths invalidate the calculation.
Further reading
Theory — what is Cronbach's alpha?
Cronbach's alpha measures the internal consistency of a set of test items, calculated from item variances and the variance of the summed scores. Every column in the calculator must represent the same person, otherwise the result is meaningless. A higher alpha usually indicates stronger covariation among items, but it does not prove they measure a single trait — redundant items can inflate the value too. There is no single universal threshold for a „good” alpha, since requirements depend on the purpose and stage of research.
Frequently asked questions
Is alpha 0.7 always good?
Does alpha prove one construct?
See also
A/B test calculator
Compare two proportions in an A/B test. Calculate conversion rates, difference, uplift, z score, p value and c
A/B test planning — sample size, MDE and duration
Plan a two-proportion experiment, estimate detectable effect and traffic duration.
ACF and PACF autocorrelation calculator
Calculate ACF and PACF across time-series lags. Review the chart, reference bounds and coefficient table.