Property taxes are calculated based on a local assessment of your home’s market value, which is typically determined based on nearby sales value comparisons, or a cost or income method. Assessments may be done every year or even once every five years, depending on state and local laws. Once your property is assessed, the value will be multiplied by the local tax rate, also called the “mill rate,” to determine what you owe. Since location impacts property taxes, your property tax bill may be higher or lower than a similar home in another county.