The three ways to find your home's market value
The market value of your home is what a buyer would pay for it today, not what you paid for it or what you think it should be worth. You can find this number through three main routes: online valuation tools, a professional appraisal, or a comparative market analysis from a real estate agent. Each method gives you a different level of detail and costs different amounts of money.
Online tools are free and take minutes. A professional appraisal costs $300 to $500 and takes a week or two. A comparative market analysis from an agent is free but comes with the expectation that you might list with them. Which one you choose depends on why you need the number — whether you're refinancing, selling, contesting your property tax assessment, or just curious.
Key Takeaways
- Online valuation tools like Zillow, Redfin, and Realtor.com give you a starting point in minutes, but they are estimates based on public data and can be off by 5 to 20 percent.
- A professional appraisal from a licensed appraiser is the most accurate method and is required by lenders when you refinance or take out a mortgage.
- A comparative market analysis from a real estate agent shows you what similar homes in your area actually sold for recently and is free, though the agent hopes you will list with them.
- Your county assessor's office has your home's assessed value on file, which is public record but is usually lower than market value because it is used for tax purposes.
- The method you choose should match your purpose — online tools for a quick check, an appraisal for a mortgage or legal dispute, and a CMA for selling.
Online valuation tools and what they actually measure
Zillow's Zestimate, Redfin's Estimate, and Realtor.com's Home Value Estimate pull data from public records — your home's size, age, lot size, recent sales of nearby homes, and property tax records — and run it through an algorithm. The result appears instantly and is free. These tools are useful for a rough sense of direction, but they are not appraisals and should not be treated as final numbers.
The margin of error on these estimates is typically 5 to 20 percent, meaning a home valued at $300,000 could actually be worth anywhere from $240,000 to $360,000. The error is larger in rural areas, in neighborhoods with few recent sales, and for homes with unusual features that the algorithm cannot account for — a recent major renovation, a view, a problem with the foundation. If your home is in a hot market with many recent sales of similar properties, the estimate will be closer to accurate.
These tools update when new sales data comes in, usually monthly. You can check multiple sites and compare their estimates to see if they cluster around the same number or diverge widely. A wide spread suggests the algorithm is uncertain, which often means you should get a professional appraisal before making a decision.
Professional appraisals: when you need an official number
A professional appraisal is a written report from a licensed appraiser who visits your home, measures it, photographs it, checks its condition, and compares it to recent sales of similar homes in your area. The appraiser then assigns a market value. This is the standard that lenders use and the number that holds up in court or in a refinance negotiation.
You order an appraisal through an appraisal management company, which your lender may recommend, or you can contact a local appraiser directly. The cost is usually $300 to $500 depending on your home's size and your region. The appraisal takes one to two weeks from order to report. If you are refinancing, your lender orders and pays for the appraisal. If you are ordering it yourself — to challenge a property tax assessment or to settle a dispute — you pay out of pocket.
An appraisal is more accurate than an online estimate because the appraiser sees the actual condition of your home and can account for renovations, damage, or features that an algorithm cannot. However, an appraisal is still an opinion, not a may provide of what your home will sell for. The appraiser's job is to estimate what a typical buyer would pay, not what your specific home will fetch on the open market.
Comparative market analysis from a real estate agent
A comparative market analysis (CMA) is a report prepared by a real estate agent that shows what homes similar to yours have sold for in the past three to six months. The agent pulls data from the local Multiple Listing Service (MLS), which is the database that real estate professionals use. A CMA is free and is often the most practical way to understand your home's value if you are thinking about selling.
To get a CMA, contact a real estate agent in your area and ask for one. You can reach out to agents who have listed homes near yours, or you can search for agents on Realtor.com or your local board of realtors' website. The agent will visit your home, ask about recent upgrades, and prepare a report comparing your home to three to five recent sales of similar homes nearby. The report shows the sale price, sale date, and key features of each comparable home.
A CMA is useful because it is based on actual sales, not estimates or algorithms. However, the agent has a financial incentive to list your home, so the CMA may be slightly optimistic about your home's value. If you get CMAs from two or three different agents, you can average them to reduce bias. A CMA is most valuable if you are actively considering selling, because the agent can also tell you about market conditions, how long homes are taking to sell, and what buyers in your area are looking for.
Your county assessor's records and property tax value
Your county assessor's office maintains a public record of your home's assessed value, which is used to calculate your property taxes. You can find this information by visiting your county assessor's website and searching by address or parcel number. The assessed value is public record and free to access.
However, the assessed value is usually lower than the market value because assessors do not revalue every home every year. In many states, assessments happen every three to five years, so your home's assessed value may lag behind the actual market. Some states cap how much the assessed value can increase in a single year, even if the market has moved faster. For these reasons, do not use the assessed value as your market value estimate — it is a starting point, not a final answer.
If you believe your assessed value is too high and is inflating your property taxes, you can challenge it through your county assessor's office. The process varies by state, but usually involves filing a formal appeal and sometimes providing an appraisal or CMA as evidence. This is one situation where paying for a professional appraisal makes sense, because the appraisal can support your case.
Comparing the three methods side by side
| Method | Cost | Time to Result | Accuracy | Best For |
|---|---|---|---|---|
| Online valuation tool | Free | Instant | ±5–20% | Quick estimate, curiosity |
| Professional appraisal | $300–$500 | 1–2 weeks | ±3–5% | Refinancing, legal disputes, tax appeals |
| Comparative market analysis | Free | 3–5 days | ±5–10% | Selling, understanding local market |
| County assessor's value | Free | Instant | Often outdated | Reference only, not market value |
What to do if your estimates disagree
If an online tool, a CMA, and an appraisal give you three different numbers, start by checking whether they are measuring the same thing. An online tool might include your home's lot in the valuation, while an appraisal focuses on the structure. A CMA might exclude a recent sale that was a foreclosure or a distressed sale, because those do not reflect normal market conditions. Read the methodology section of each report to understand what went into the number.
If the numbers still diverge widely — say, more than 10 percent apart — the reason is usually that your home has features the algorithm or the comparable homes do not capture. A recent major renovation, a unique floor plan, a problem with the roof, or a location near a highway can all cause estimates to spread. In this case, a professional appraisal is worth the cost, because the appraiser will explain the reasoning behind the number and account for these features explicitly.
If you are refinancing and the appraisal comes in lower than you expected, you have a few options: you can ask the lender to order a second appraisal (some lenders will do this), you can provide the appraiser with documentation of recent upgrades they may have missed, or you can shop for a different lender. Do not assume the first appraisal is wrong just because it is lower than an online estimate — appraisals are typically more accurate than algorithms.
Frequently Asked Questions
How often should I check my home's value?
If you are not planning to sell or refinance, checking once a year is enough. If you are actively refinancing or selling, check every few months, because market conditions can shift. Online tools update monthly as new sales data comes in, so you can check them for free anytime without wearing out your welcome with agents.
Can I use an online estimate to refinance my home?
No. Lenders require a professional appraisal ordered through an appraisal management company. The lender will order this for you and deduct the cost from your closing costs or add it to your loan balance. You cannot use a Zillow estimate or a CMA in place of an appraisal for a mortgage transaction.
What if I think my home is worth more than the appraisal says?
You can ask the appraiser to reconsider if you have documentation of recent upgrades they may have missed — receipts for a new roof, kitchen remodel, or HVAC system. Provide this in writing. If the appraiser does not change the value, you can request a second appraisal from a different appraiser, though some lenders charge for this. If you are selling, a lower appraisal may mean adjusting your asking price to match the market.
Is my home's value the same as what I can sell it for?
Market value and sale price are related but not identical. Market value is what a typical buyer would pay under normal conditions. Your actual sale price depends on how motivated the buyer is, how many other buyers are competing, and how well your home shows. A home valued at $300,000 might sell for $285,000 in a slow market or $315,000 in a hot one.
Do I need an appraisal to challenge my property tax assessment?
Not always. Many counties allow you to challenge an assessment based on recent sales of comparable homes or on an error in the assessor's records — like an incorrect square footage. An appraisal strengthens your case if the assessed value is significantly higher than market value, but check your county's appeal process first to see what evidence they accept.