Cronbach Alpha Calculator
Calculate Cronbach alpha for questionnaire reliability using number of items, sum of item variances, and total score variance.
About this method
Cronbach alpha estimates internal consistency: how closely related the items in a scale are. Values above 0.70 are commonly considered acceptable for research use.
Frequently Asked Questions
What is acceptable Cronbach alpha?
A common benchmark is 0.70 or higher for acceptable internal consistency.
Can alpha be too high?
Yes. Values above 0.95 may suggest redundant items.
Is Cronbach alpha enough to validate a questionnaire?
No. It is one reliability indicator. Validity, factor structure, and content relevance should also be assessed.