Determining the Length of a course

Sindy,

Here is an article you might find helpful here:  

https://community.articulate.com/articles/how-to-calculate-the-seat-time-for-your-e-learning-course

Some people use word counts from the storyboard and calculate the time based on the average narration speed (e.g., ~150 words per minute). Others use slide counts.

From my experience, those are somewhat arbitrary.  Nicole Legault has an excellent article here that explains why things are not always what they seem: 

https://community.articulate.com/articles/how-to-calculate-the-seat-time-for-your-e-learning-course

My best estimates come from reviewing courses I've created in the past and comparing the final draft storyboards.  In some situations, I've found the need to move content to "additional resources" when seat time was getting close to the 30-minute mark.  

I hope this helps!