Property Taxes Explained: How They're Calculated, Why They Rise, and How to Appeal

Property taxes represent one of the largest ongoing costs of homeownership — averaging $2,795 annually nationwide, but exceeding $10,000–$15,000 annually in high-tax states like New Jersey, Illinois, and Connecticut. Unlike mortgage payments, property taxes aren't fixed and can increase every year as assessed values change. Yet property tax assessment errors are surprisingly common — estimates suggest 30–60% of properties are over-assessed — and most homeowners don't know they have the right to formally appeal. Understanding how taxes are calculated and how appeals work can save $500–$2,000 per year.

How Property Taxes Are Calculated

• Assessed Value vs. Market Value

  Your tax bill is based on assessed value, not market value. Many jurisdictions assess at a fraction of market value (assessment ratio: 40–100%). If your home is worth $400,000 and your county uses a 70% assessment ratio, your assessed value is $280,000. The assessor updates values periodically — annually in some states, every 5 years in others.

• Mill Rate (Tax Rate)

  Tax rate is expressed as mills: 1 mill = $1 per $1,000 of assessed value. Example: 25 mill rate on $280,000 assessed value = $7,000 annual tax. Mill rates vary by jurisdiction and fund schools, municipal services, fire, and special districts. Rates change annually based on budgets — even if your assessment stays flat, your tax bill can rise if the rate increases.

• Homestead and Senior Exemptions

  Most states offer homestead exemptions for primary residences — typically $10,000–$50,000 off assessed value. Senior exemptions provide additional reductions for homeowners 65+ meeting income requirements. File for exemptions promptly — many are not applied automatically and have annual deadlines. Collectively, available exemptions average $1,000–$2,000 in annual savings for qualifying homeowners.

Approximately 30–50% of homeowners who formally appeal their property tax assessment receive a reduction. The process: request your property record card from the assessor's office (free) and check for errors in square footage, bedroom/bathroom count, lot size, and condition rating. Research comparable sales (comps) in the past 6–12 months — homes similar in size and condition that sold for less than your assessed value support your appeal. File the appeal form (typically due within 30–90 days of receiving your assessment notice) and present the comps at your hearing. Many jurisdictions allow informal reviews before the formal hearing — resolve at this stage if possible for faster results.