How to calculate property taxes

Are there any sites out there that index property taxes for different areas? How do you calculate property tax when evaluating a property.

in some areas, you can get on the tax appraisal website and they will show non exempt taxes for current year. you never know what the next year will bring in either appraisal or assessment but it is as close as you can get without a crystal ball. unexempt is the tax without regard to the individual living owning it, after a year you will be eligible for what ever exemptions apply. conversely, if there are current exemptions on the property those typically are through the current year regardless of change of ownership, at least in the dfw metro area appraisal districts.