Comparable sales are the single strongest piece of evidence in a property tax appeal. They show what similar homes near you actually sold for. If those recent sale prices sit below your assessed value, you may be overpaying. However, the good news is simple. Most homeowners can gather this proof themselves, for free, in an afternoon. This guide walks you through it in plain steps.
Comparable Sales: Where to Start
Start with your assessment notice. Your county assessor mails this yearly. It lists your assessed value and the deadline to appeal. Read it carefully. That number is the target you are testing.
Next, pull recent sales near you. Your county assessor or appraisal district website (a .gov site) often lets you search sold properties for free. Many counties post this data publicly. For example, you can look up sales by street, subdivision, or map view.
Good comparable sales share key traits with your home. Aim for similar square footage, age, lot size, and location. In most cases, sales within the past 12 months and within a mile or two work best. Pick homes as close to yours as you can.
The Evidence That Actually Works
Assessors and review boards respond to hard numbers, not feelings. A stack of comparable sales beats a long complaint every time. Your job is to show that similar homes sold for less than your assessed value.
For example, if your home is assessed at $340,000 but three near-identical homes sold for around $300,000, that gap is your case. Print each sale. Note the address, sale date, price, square footage, and beds and baths.
Groups like the International Association of Assessing Officers (IAAO) set the standards assessors follow. They stress fair, market-based values. As a result, sales-based evidence is exactly the language your assessor already uses.
| Step | What to gather | Where to find it |
|---|---|---|
| 1 | Your assessed value and appeal deadline | Your assessment notice from the assessor |
| 2 | 3–5 recent comparable sales | County assessor or appraisal district (.gov) site |
| 3 | Sale price, date, size, beds/baths for each | Public property records |
| 4 | Photos of any damage or needed repairs | Your own phone |
| 5 | Your assessor’s record card for errors | County assessor site or office |
Also check your property record card for mistakes. Wrong square footage or an extra bathroom can inflate your value. Fixing one error can lower your bill on its own.
The Deadline You Cannot Miss
The appeal window is short, and it is unforgiving. Typically it runs only a few weeks after notices go out. Miss it, and you usually wait a full year for another chance.
How Comparable Sales Can Pay Off
The payoff comes when your evidence lowers your assessed value. A lower value means a lower tax bill. Your savings depend on your local rate, sometimes called the mill rate (the tax per $1,000 of value).
Groups like the Tax Foundation and the Lincoln Institute of Land Policy publish state-by-state rate data. They confirm that rates and median bills vary widely. However, no outside chart replaces your own county’s current figures. Always verify those locally.
Common Mistakes and How to Avoid Them
The biggest mistake is picking weak matches. A larger, newer home two towns over is not a fair comparison. Stay close in size, age, and neighborhood. Quality beats quantity here.
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Another common slip is using listing prices instead of actual sold prices. Only closed sales count as real market proof. Also, avoid emotional arguments about your bill. Boards weigh comparable sales, not frustration, so keep your file factual and neat.
Finally, do not wait until the last day. Give yourself time to gather records and double-check your math. Bring copies for the board, and keep a set for yourself.
Frequently Asked Questions
How many comparable sales do I need?
Three to five strong matches usually make a solid case. More is fine if they are close to your home. Focus on recent, nearby sales of similar properties.
Where can I find sale prices for free?
Your county assessor or appraisal district website often posts them. These are public .gov records in many areas. The U.S. Census Bureau also offers helpful housing data for context.
What if my home has damage the assessor did not see?
Photograph it and bring the pictures. Needed repairs can lower fair market value. Pair this evidence with your comparable sales for a stronger appeal.
Do I need to hire someone to appeal?
In most cases, no. Many homeowners file successfully on their own. If your case is large or complex, you may choose professional help, but it is not required.
Will appealing raise my taxes instead?
Typically an appeal reviews whether your value is too high. Assessors generally will not punish you for asking. Still, confirm how your county handles reviews before you file.
Ready to lower your bill?
You can appeal your property taxes yourself — most homeowners can, and it is free. Start with our step-by-step appeal guides to gather the evidence, hit the deadline, and make your case.
Lowering your tax bill? Check your home insurance too.
Property tax isn’t the only home cost worth a second look. Many homeowners are overpaying for home insurance without knowing it — comparing quotes is a fast way to keep more of your money.
Sources & How to Verify
The figures and rules on this page come from official and authoritative sources. Property tax rates, median bills, and exemption amounts reset every year and vary by state, county, and school district — so always confirm the current figure, any exemption, and any deadline with your county assessor before you act. We are an independent educational resource, not a government agency or a tax-appeal service, and this page is not legal, tax, or financial advice.
- Tax Foundation: taxfoundation.org — property taxes by state & county
- U.S. Census Bureau: census.gov — median property tax paid and home values
- Lincoln Institute of Land Policy: lincolninst.edu — property-tax research and the 50-state data
- IAAO (assessment standards): iaao.org — how assessors are supposed to value property
- Your county assessor & state Department of Revenue: search “[your county] assessor” for your exact rate, exemptions, and appeal deadline
Content last reviewed July 2026. If you notice an outdated figure, please contact us.
Related Guides
- How to Appeal & Lower Your Property Taxes
- Exemptions & Relief
- Property Tax Basics
- More in This Category
- Property Tax by State
- Property Tax Glossary
Informational only — not legal, tax, or financial advice. Know Property Tax is an independent educational resource, not a government agency, a county assessor, a law firm, or a tax-appeal service, and this page does not provide legal, tax, or financial advice. Property tax rates, median bills, exemption amounts, and deadlines change every year and vary by state, county, and school district, and any estimate is illustrative only. Always confirm your rate, any exemption, and any deadline with your county assessor and a licensed professional before you act.