Enter the number of items, average covariance between pairs, and the average variance into the calculator to determine Cronbach’s alpha.

## Cronbach Alpha Formula

The following formula is used to calculate Cronbach alpha.

a = (N*C) / ( v + (N-1)*C)

- Where a is the coefficient alpha
- N is the number of items
- C is the covariance between item pairs
- v is the average covariance

## Cronbach Alpha Definition

Cronbach’s alpha, also known as coefficient alpha, is a measure of the internal consistency of a test. In other words, how reliable the test is at predicting an outcome.

## Example

How to calculate cronbach’s alpha?

**First, determine the number of items.**This is typically the total number of questions on the test.

**Next, determine the covariance between items.**Calculate the covariance between items.

**Next, determine the variance average.**Calculate the average variance of the test.

**Finally, calculate the alpha coefficient.**Calculate the reliability using the formula above.

## FAQ

**What is internal consistency?**

Internal consistency is a measure of the variance in results between the same test given multiple times.