How to calculate the tax

[Navya Rajput]

Hi I am looking for a way to calculate the taxes for the properties that I am evaluating. For eg If I am looking for property in Worcester, MA. I am looking at this site http://www.worcesterma.gov/finance/assessing. But the numbers doesn't match with the zillow's estimates of per month taxes on the property. Please can anyone tell me the correct way to calculate the taxes on the property?

Thank you :)

Regards

Navya