Cumulative Variance Explained Calculator

Measure retained information from ranked components accurately. Compare cutoffs, targets, and scree behavior instantly now. Choose optimal components using clear cumulative variance evidence wisely.

Result Preview

Enter ranked eigenvalues, choose a target variance threshold, and submit the form. Your result will appear here above the calculator.

Calculator Input

Use commas, spaces, semicolons, or new lines. The calculator will sort values from highest to lowest automatically.

Example Data Table

This example shows how retained variance grows as more principal components are included.

Component Eigenvalue Explained Variance (%) Cumulative Variance (%)
PC14.8048.0048.00
PC22.6026.0074.00
PC31.4014.0088.00
PC40.707.0095.00
PC50.303.0098.00
PC60.202.00100.00

Formula Used

Explained Variance for Component i

Explained Variance (%) = (Eigenvaluei / Sum of All Eigenvalues) × 100

Cumulative Variance up to Component k

Cumulative Variance (%) = Sum of explained variance percentages from component 1 through component k

This method is widely used in principal component analysis to identify how many components preserve a desired share of total information.

How to Use This Calculator

  1. Enter a dataset or project name for easier reporting.
  2. Paste eigenvalues separated by commas, spaces, semicolons, or line breaks.
  3. Set the target cumulative variance percentage, such as 85%, 90%, or 95%.
  4. Choose how many decimal places you want displayed.
  5. Click the calculate button to generate the ranked variance summary.
  6. Review the metrics, suggested elbow point, and detailed component table.
  7. Use the CSV or PDF buttons to export your results.

Frequently Asked Questions

1. What does cumulative variance explained mean?

It shows the running percentage of total variance captured as you include more ordered components. It helps decide how many components preserve enough information for analysis or modeling.

2. Why are eigenvalues important here?

Each eigenvalue represents the amount of variance captured by one component. Larger eigenvalues mean stronger components and greater influence on total retained variance.

3. What target variance should I use?

Common thresholds are 80%, 90%, and 95%. The best choice depends on your tolerance for information loss, model complexity, and downstream task requirements.

4. Does the order of eigenvalues matter?

Yes. Components should normally be assessed from highest to lowest eigenvalue. This calculator automatically sorts values in descending order before computing cumulative results.

5. What is the Kaiser count?

It counts components with eigenvalues at least equal to one. In many PCA workflows, those components are considered meaningful because they explain at least as much variance as one standardized variable.

6. What does the elbow point suggest?

The elbow point approximates where explained variance gains start slowing sharply. It is a helpful screening signal, not a strict rule, when selecting components.

7. Can I use this for factor analysis too?

Yes, the variance logic is similar, but interpretation depends on the extraction method and rotation choices. Confirm your workflow before making final decisions.

8. What happens if my values include zeros?

Zero eigenvalues are allowed. They simply add no explained variance. However, the combined total of all eigenvalues must still be greater than zero.

Related Calculators

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.