Cronbach's Alpha Calculator
Paste your item scores below and get instant reliability analysis with item-total correlations, alpha-if-deleted, and an APA-ready citation.
How to Use This Calculator
1. Prepare your data: Each row represents a respondent and each column represents an item (question) in your scale. Values should be numeric (e.g., Likert scale responses: 1-5).
2. Paste your data: Copy your data from Excel, SPSS, or any spreadsheet. Columns can be separated by tabs, commas, or semicolons.
3. Click Calculate: The tool computes Cronbach's alpha, item-total correlations, and alpha-if-deleted for each item.
4. Interpret results: Alpha values above .70 are generally considered acceptable for research purposes (George & Mallery, 2003). Items flagged in the analysis table may be reducing your scale's reliability.
About Cronbach's Alpha
Cronbach's alpha (Cronbach, 1951) measures the internal consistency of a scale or questionnaire. It estimates how closely related a set of items are as a group, making it one of the most widely used reliability statistics in social science research.
The formula is: α = (k / (k-1)) × (1 - Σσ²ᵢ / σ²ₜ), where k is the number of items, σ²ᵢ is each item's variance, and σ²ₜ is the total score variance.
Learn more in our detailed tutorials: How to Calculate Cronbach's Alpha in Excel and How to Calculate Cronbach's Alpha in SPSS.