Property Tax Appeal Calculator
Estimate your potential property tax savings if you successfully appeal your home's assessed value using comparable sales data.
Property tax appeal is the formal process of challenging your property’s assessed value when you believe it is higher than the true market value, resulting in an unjustly high property tax bill.
Core formulas: Annual Property Tax = Assessed Value × Mill Rate ÷ 1,000 Potential Tax Savings = (Current Assessed Value − Proposed Assessed Value) × Mill Rate ÷ 1,000 Overassessment % = (Assessed Value − Market Value) ÷ Market Value × 100
Where:
- Assessed Value = the value your local government assigns to your property for tax purposes (often 80–100% of market value, but varies by jurisdiction)
- Mill Rate = tax rate expressed per $1,000 of assessed value (e.g., 12 mills = $12 per $1,000)
- Market Value = what your property would actually sell for
Worked example: Assessed value: $420,000 | Mill rate: 14 mills | Market value (comps): $375,000 Current tax = $420,000 × 14 ÷ 1,000 = $5,880/year If appeal succeeds at $375,000: $375,000 × 14 ÷ 1,000 = $5,250/year Annual savings: $630 | 5-year savings (before next reassessment): $3,150
How to build a winning appeal:
- Gather 3–5 recent comparable sales (within 6–12 months, similar size/age/condition)
- Document property defects (structural issues, flooding risk, needed repairs)
- Review assessment records for factual errors (wrong square footage, bedroom count, lot size)
- Hire an appraiser if the stakes are high (appraisal costs $300–$500 but can save thousands)
Success rates: Homeowners who appeal and provide comparable sales data win or achieve partial reductions roughly 40–60% of the time. The median tax reduction for successful appeals is $500–$1,500 per year.