Does anyone know how to calcuate a price for replacing drywall? If the supplies are just $150, is $1200 too much for the labor?

Absolutely! Are you looking to hire someone or are you looking to give an estimate for someone? How many sheets of drywall is it? What is the square footage? Is it just to hang it or hang and finish?

A friend is starting a handyman business and someone is asking them to replace drywall in a 12x13 room. The people she is thinking of using is charging $940 in labor. I'd like to find some software for them that gives them estimates of fair/average costs.

Isn't that something. As soon as I previously answered your first question, I took the price of material assuming all of the $150 went to drywall alone at a below market price of $5.00 per sheet, also assuming you were using all 4x8 sheets. Then figured the square footage by the amount of drywall and multiplied that by $1.00 per square foot to hang and finish. My estimate came to $960 for labor. $1.00 per square foot is a fair price to hang and finish sheetrock. You may want to go a little lower than the other price to be competitive.

This is a fair price I own a drywall co materials for drywall are quit cheap but the labor is not when I price patching I charge 60.00 per hour

The price in pittsburgh is about 35 to 40 dollars a 4x 12 sheet. That is material and labor, but a smaller job will cost more. But this should give you an idea.

Installing drywall and REPLACING drywall are two completely different jobs. Most professional drywallers can do almost any job in the blink of an eye. They are efficient, fast, and do a job most would walk away from. Just get a few bids to assure yourself the cost is in line.