Comparing Two VIs in LabVIEW

Updated Oct 10, 2018

Reported In


  • LabVIEW Professional

Issue Details

I have two different versions of the same VI. How can I efficiently compare them and find differences and similarities?


Use the VI Comparison feature by opening LabVIEW and selecting Tools»Compare»Compare VIs... This will bring up the Compare VIs dialog box:

  1. In the dialog box, select the VIs you want to compare.  Note that the VIs must be open so they are loaded into LabVIEW's memory. 
  2. Choose which items from the VI you would like to compare by placing a check next to that item (e.g., Front Panel, Block Diagram, etc.)
  3. When you have selected the VIs to compare and the attributes to compare, click the Compare button. This will bring up the two VIs side-by-side with the Differences dialog box below.
  4. Explore the difference between the VIs.
    • Click on a difference in the left pane to see its details. The details will describe what type of difference each item is referring to (e.g., Deleted/Added item, Value difference).
    • Place a check next to the Circle Differences option. This will place a red circle around the item in each VI that a particular difference is referring to.
    • Click on the Show Detail button, and it will highlight the particular detail you have selected for a particular difference (and also place a check next to the detail).

Additional Information

This feature is only available in LabVIEW Professional. If you don't have LabVIEW Professional, you can try programmatically comparing VIs, you can also check out the example Reference Utility for Programmatically Comparing (Diffing) VIs


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