The units check feature checks the model equation for the consistent use of units of measurement. You can check the units in a model using the Model>Units Check command or by holding down the Ctrl key and pressing U (Ctrl + U). Depending on how you have configured your Analysis Toolset or which toolset you have loaded, there might also be a tool 
that you can click on to check units.
When you check the units in a model, Vensim will report a list of errors that have been found. Units check errors do not prevent simulation, but fixing units problems can sometimes find problems that might otherwise have been overlooked. If you do not specify units of measurement for model variables, checking the units will simply report the name of each variable that has not had its units specified.
The most common sources of units errors are mistyped units names and missing synonyms. After correcting these, however, there are likely to remain errors of a more substantive nature. If you have multiplied instead of dividing, units checking will find that quickly. The potential for finding serious problems quickly, combined with the value and clarity that come from specifying units, make performing units checking a very worthwhile activity.
