The three ways to find your home's value
You can find your home's estimated value through a public tax assessment, an online valuation tool, or a professional appraisal. Each method gives you a different number because they use different data and serve different purposes. A tax assessment is what your local government thinks your home is worth for property tax purposes. An online estimate pulls from recent sales of similar homes in your area. A professional appraisal is what a licensed appraiser determines after walking through your home and comparing it to recent sales — this is the most expensive option but also the most detailed.
The method you choose depends on why you need the value. If you are refinancing a mortgage, your lender will order an appraisal. If you are selling and want a rough starting point, an online tool is faster and free. If you are contesting your property taxes, the tax assessment is what matters.
Key Takeaways
- Your county assessor's office publishes property values online for free, usually searchable by address on the county website.
- Online valuation tools like Zillow, Redfin, and Realtor.com estimate value based on recent sales but can be off by 5 to 20 percent depending on how many comparable homes sold recently in your area.
- A professional appraisal ordered by a lender costs $300 to $500 and is required for mortgage refinancing or purchase loans.
- The assessed value on your property tax bill is often lower than market value and is used only for tax calculation, not for selling or refinancing.
Finding your assessed value through the county assessor
Your county assessor maintains a public record of every property's assessed value. This is the value used to calculate your property taxes. You can find it by visiting your county assessor's website and searching by address or parcel number. Most counties let you search for free without creating an account.
The assessed value is usually lower than what your home would sell for on the open market. It exists only for tax purposes. However, it is a real number tied to your property and updated on a schedule set by your state — some counties reassess every year, others every three to five years. If you think your assessment is too high, you can file a formal challenge, but the process and deadline vary by state.
Using online home valuation tools
Websites like Zillow, Redfin, Realtor.com, and Trulia publish estimated home values based on recent sales of similar homes, property records, and in some cases, machine learning models trained on millions of sales. These estimates are free and instant. You type your address and get a number called a "Zestimate" (Zillow), "Redfin Estimate," or similar.
These tools are useful for a rough sense of your home's market value, but they are estimates, not appraisals. The margin of error can be 5 to 20 percent depending on how many homes like yours sold recently in your neighborhood. In a hot market with many recent sales, the estimate is usually more accurate. In a rural area or a neighborhood with few recent sales, the estimate can be significantly off. Do not use an online estimate as your final number for a major financial decision.
You can also check multiple sites — if Zillow says $450,000 and Redfin says $465,000, your actual value is probably somewhere in that range. The sites use slightly different data and algorithms, so variation between them is normal.
Getting a professional appraisal
A professional appraisal is an official document prepared by a licensed appraiser who visits your home, measures it, inspects its condition, and compares it to recent sales of similar homes in your area. The appraisal is what lenders use to decide how much they will lend you. If you are refinancing a mortgage or taking out a home equity loan, your lender will order the appraisal and you will pay for it — typically $300 to $500 depending on your home's size and location.
You cannot order an appraisal on your own and have it count for a mortgage. The lender must order it from an appraiser on their approved list to ensure independence. However, if you want a value estimate before you list your home for sale, you can hire an independent appraiser yourself. This costs more than an online estimate but less than waiting for a lender's appraisal, and it gives you a professional opinion before you commit to a price.
What to do if your assessed value seems wrong
If your property tax bill shows an assessed value that seems too high, you can file a formal challenge called an assessment appeal or assessment review. The process and deadline vary by state and county. Some counties have a specific appeal period each year (often 30 to 60 days after the assessment is mailed), while others allow appeals year-round.
To file an appeal, contact your county assessor's office and ask for the appeal form and deadline. You will need to show evidence that your assessment is incorrect — this might be a recent appraisal, recent sales of comparable homes, or documentation of damage or needed repairs that lower your home's value. The assessor will review your evidence and either adjust the value or uphold it. If you disagree with the result, some states allow a further appeal to a county board or court, but this is rare and usually expensive.
How recent sales in your area affect your home's value
Online valuation tools and professional appraisals both rely on recent sales of similar homes — called "comparables" or "comps" — to estimate your home's value. A home that sold three months ago for $425,000 two blocks away tells you more about your home's value than a home that sold five years ago across town. The more recent the sale and the closer the location, the more weight it carries.
If your neighborhood has had few recent sales, any estimate will be less reliable. If your home is unusual — a custom build, a historic property, or something with special features — finding true comparables becomes harder, and online estimates become less accurate. In these cases, a professional appraisal is worth the cost because the appraiser can explain their reasoning and account for features that an algorithm might miss.
Frequently Asked Questions
Is the Zillow estimate accurate?
Zillow's estimate is a starting point, not a final answer. It can be off by 5 to 20 percent depending on how many similar homes sold recently near you. In neighborhoods with many recent sales, it is usually closer to accurate. In rural areas or neighborhoods with few sales, it can be significantly wrong. Use it alongside other sources, not alone.
Do I need an appraisal to sell my home?
No. You set the asking price yourself, usually with help from a real estate agent who prepares a comparative market analysis. A buyer's lender will order an appraisal before they close, but that appraisal is for the lender, not for you. You do not pay for it or control it.
Can I use an online estimate to refinance my mortgage?
No. Your lender will order a professional appraisal. The appraisal determines how much equity you have and how much you can borrow. An online estimate does not count.
What if the appraisal comes in lower than I expected?
If a lender's appraisal is lower than the purchase price or your expected value, you can ask the appraiser to reconsider if you believe there is an error in their comparables or their assessment of your home's condition. You can also hire an independent appraiser for a second opinion, though this costs extra. If the appraisal is correct, you may need to lower your asking price, increase your down payment, or walk away from the deal.
How often does my assessed value change?
This depends on your state and county. Some reassess every year, others every three to five years. Check your county assessor's website or call their office to find out the schedule for your area. You can also ask when your next reassessment is due.