Prices estimated by a roof calculator will be approximate, and depend upon geography, cost of living and real estate rates in your location. The kind of roofing contractors you hire for the project will also impact the projected cost, as will the need for insurance and the quality of materials used.
Pricing estimates are usually averaged rates of regional estimates received from different parts of the country. The rates my differ by $30 to $50 a square depending on which state you live. The experience and skill level of your roofing contractor will also influence the estimate. Sometimes you’ll get a very cheap quote, but it may come from a contractor who is out of work and in urgent need of work. It’s also possible that such a contractor might be uninsured, increasing your risk as house owner.
New and inexperienced contractors will quote lesser rates as they gain work experience on the job. It may be that the contractor isn’t aware of actual costs and may be losing out on profit. But on the other hand, it could be that he’s using poor quality material or similarly inexperienced sub-contractors, which can lead to your roof leaking shortly after installation. A roof calculator can thus be a guard against getting cheated.