Question about estimating cost of demo in Pittsburgh

[Jeremy Pace]

I'm trying to come up with a way to estimate the cost to gut a unit.  I haven't ever tried to calculate out a space this large before, and I was wondering if anyone had any tips or tricks they use when trying to figure out the cost to gut a whole unit down to the studs.

If it helps, the unit is a 3/1 kitchen, dining room, living room.  12 foot ceiling throughout.

Thanks!