What to charge per square to tear off and install shingles

Same price as the shingle cost per sq. ft.

How many layers?
How steep is the roof slope?
What kind of shingles? (asphalt? Slate? Metal? Other?)
How much for a dumpster or debris removal?
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Labor to rip-off and install can exceed the cost of shingles by many times and is a very poor way to price any roof job.

In the Atlanta area, the average labor price to rip off a 1 layer average slope 3 tab house roof and reshingle is a bit more than the cost of the shingles. Does not include new vents, skylights, metal roofing, repairs etc. Perhaps I should have been a bit more explanatory.

Cost to install new shingles will depend, but in general around $200 - $300 per sq

http://www.rempros.com/installation-prices/cost_to_repair_roof.html