We use a detached garage as workspace & storage for a product-based business. How do I calculate sq ft? Do I calculate as a separate building part of our house?

[RichardK]

Yes, absolutely, if you have designated space inside the garage for your business.  You can add the square footage of the garage to the total square footage of the home, then take the deduction for the dedicated business space.

How to get to the area to enter your home office :   While inside the software and working on your return, type Schedule C in the Search at the top of the screen (you may see a magnifying glass there).  There will be a popup that says Jump to Schedule C.  Select that to get to the general area. 

Then:

·        select Edit next to your business (if it is there)

·        scroll to Business Expenses

·        then Home Office

Follow through all the areas in the Business section of the TurboTax software and it will provide you with a lot of assistance. You'll notice blue links that have more information and details about the particular sections that will be extremely helpful. 

Also, this link may be helpful to you IRS Small Business Help Center .