Property Tax Protest Calculator

About the Property Tax Protest Calculator

A property tax protest begins with one simple question: is your property assessed higher than it should be? By comparing your assessed value to actual comparable sales in your area, you can determine whether you're overpaying and by how much. This calculator helps quantify the overassessment and the resulting annual overpayment.

Enter your assessed value and up to five comparable sales. The calculator averages the comps to estimate your property's fair market value, then compares that against your assessment. If the assessment exceeds the comp average, you have a strong case for a protest. The overpayment is calculated using your local mill rate.

Many homeowners and investors pay thousands more than necessary in property taxes simply because they don't challenge their assessments. This calculator gives you the data foundation to decide whether a protest is worth pursuing and what your potential savings could be.

Homebuyers, investors, and real-estate professionals all benefit from precise property tax protest figures when evaluating properties, negotiating deals, or planning long-term investment strategies. Save this calculator and revisit it whenever market conditions or your financial situation changes.

When This Page Helps

Knowing whether you're overassessed is the first step in any property tax reduction strategy. This calculator objectively compares your assessment to market data, removing guesswork and giving you concrete numbers to present in a protest hearing.

How to Use the Inputs

1. Enter your property's current assessed value.
2. Enter the sale prices of 3–5 comparable properties (similar size, age, condition, location).
3. Enter your local mill rate.
4. The calculator averages the comp sales to estimate fair market value.
5. View the overassessment amount and annual overpayment.
6. Use the results to determine if filing a protest is worthwhile.

Example Calculation

Tips & Best Practices

• Choose comps that sold within the last 6–12 months and are as similar as possible.
• Adjust comp prices for differences in square footage, lot size, and condition.
• More comps strengthen your case—aim for 4–5 if available.
• Include distressed sales only if they reflect genuine market conditions.
• Document any condition issues in your property that reduce its value relative to comps.
• Photograph property defects that affect value but may not appear in assessor records.

Building Your Protest Case

Start by pulling 5–10 comparable sales from county records or MLS. Narrow them to the 3–5 most similar properties. Adjust for differences in size, condition, lot, and amenities. Calculate the adjusted average and compare to your assessed value.

Common Assessor Errors

Assessors frequently have incorrect square footage, lot size, bedroom/bathroom counts, or condition ratings. Review your property card (available from the assessor's office) for errors—correcting factual mistakes is often the easiest path to reassessment.

Protest Timeline and Process

Most protests must be filed within 30–90 days of receiving your assessment notice. The process typically involves an informal review, followed by a formal hearing if needed. Prepare a clear presentation with your comp analysis, photos, and any supporting documents.

Frequently Asked Questions

• What makes a good comparable sale?

  A good comp is a property that sold recently (within 6–12 months), is within 0.5–1 mile of your property, has similar square footage (±10–15%), similar age, similar lot size, and similar condition. The more similar the comp, the stronger your protest argument.

• How much overassessment justifies a protest?

  Any overassessment can be protested, but practically, the savings should exceed your time and costs. If the overassessment produces annual savings of $300+, it's generally worth the effort. Larger overassessments of 10–20%+ make even stronger cases.

• Can I use Zillow or Redfin estimates as comps?

  Online estimates (Zestimates, etc.) are not accepted as evidence in most jurisdictions. You need actual closed sale prices from MLS data, county records, or title companies. Your real estate agent or an appraiser can provide verified comp data.

• What if my comps show I'm underassessed?

  If comparable sales are higher than your assessed value, your property may be underassessed. In that case, a protest would not be beneficial. However, don't worry—filing a protest rarely triggers an increase in assessment in most jurisdictions.

• How do I adjust comps for differences?

  Apply adjustments for square footage ($30–$100/sqft depending on market), lot size ($5,000–$20,000+ per significant difference), age/condition ($5,000–$30,000), and amenities (pool, garage, updated kitchen). Appraisers use standardized adjustment grids.

• Should I hire a professional for my protest?

  For overassessments under $50,000, DIY with good comp data usually works. For larger amounts or complex properties, a property tax attorney or consultant (often working on contingency) can improve outcomes. They typically charge 25–40% of first-year savings.