As a general rule, if your percentage increase year over year is larger than the average municipal change (4.5 per cent), you may experience an increase due to the reassessment. If your percentage change is relatively close to the average, you may not experience an assessment-related tax increase or decrease. If your percentage change is less than the average, you may experience an assessment-related tax decrease.You can simply calculate if you have had an assessment-related increase by multiplying your interim tax bill by two and comparing it to your prior year's total tax bill.