What determines your home's value

Your home's value is set by what a buyer would pay for it right now in your local market. That price depends on four things: what similar homes nearby sold for recently, the condition of your house, what you have inside it (square footage, number of bedrooms, lot size), and how much demand exists in your area. A house worth $300,000 in one county might be worth $150,000 in another, even if the houses look identical.

The market value is different from what you owe on your mortgage, what you paid for it years ago, or what you think it should be worth. Market value is what matters when you sell, refinance, or need to know your net worth. It shifts with interest rates, local job growth, school quality, and how many homes are for sale at the same time you are.

Key Takeaways

  • Your home's market value comes from recent sales of similar homes in your area, not from what you paid or what you owe.
  • Online estimates from Zillow, Redfin, and Realtor.com are free and fast but often off by 5 to 20 percent because they use incomplete data.
  • A professional appraisal costs $300 to $500 and is the most accurate method, required by lenders when you refinance or take out a home equity loan.
  • A comparative market analysis from a real estate agent is free and based on actual recent sales in your neighborhood, making it more reliable than online tools alone.
  • Your assessed value for property taxes is usually lower than market value and is set by your county assessor, not by you.

Online home value estimates and their limits

Websites like Zillow, Redfin, Realtor.com, and Trulia let you type your address and see an estimated value in seconds. These tools are free and they update regularly, so they are useful for a rough sense of direction. But they work from public records, prior sales data, and algorithms—not from a person who has walked through your house. They do not know if you have a finished basement, a new roof, or foundation problems.

These estimates are often off by 5 to 20 percent, sometimes more in rural areas or in neighborhoods where homes do not sell frequently. If your estimate says $400,000 but the actual range is $320,000 to $480,000, that is a $160,000 spread. Use online tools to get a starting point, but do not treat them as final. They are most useful when you compare the same house across multiple sites—if Zillow says $350,000 and Redfin says $365,000, the real value is probably somewhere between them.

Professional appraisals: when you need one and what it costs

A professional appraiser is a licensed person who inspects your home in person, measures it, photographs it, and compares it to recent sales of similar homes. An appraisal costs between $300 and $500 depending on your home's size and location. The appraiser produces a written report that lenders accept as proof of value.

You need an appraisal when you refinance a mortgage, take out a home equity loan, or settle a divorce or estate. Your lender will order it and you will pay for it, usually at closing. If you are just curious about your home's value and not borrowing money, an appraisal is more expensive than other methods and not necessary. However, if you are planning to sell or refinance within the next year, getting an appraisal now tells you what to expect and whether it makes financial sense to move forward.

Comparative market analysis from a real estate agent

A real estate agent can pull a comparative market analysis (CMA) for free. This is a report showing what homes similar to yours sold for in the last 30 to 90 days in your neighborhood. The agent looks at homes of similar size, age, condition, and lot size, and adjusts for differences—for example, if a comparable home sold for $350,000 but has an extra bedroom, the agent might subtract $20,000 to account for that difference.

A CMA is more reliable than an online estimate because it is based on actual closed sales, not algorithms. The agent has access to the Multiple Listing Service (MLS), which shows real transaction prices, not just asking prices. You do not have to hire the agent to sell your home to get a CMA; many agents will prepare one for free in hopes you will list with them later. Call three or four agents in your area and ask for a CMA. The reports will likely be similar, and that range is a solid estimate of your home's value.

Tax-assessed value versus market value

Your county assessor sets a tax-assessed value for property tax purposes. This is usually lower than market value because assessors do not reassess every home every year in most states. You can find your assessed value on your property tax bill or on your county assessor's website. It is public information.

Assessed value and market value are not the same thing. Your home might have a market value of $400,000 but an assessed value of $320,000 if it was last reassessed five years ago. Some states reassess frequently; others do not. A few states reassess only when a home sells. Do not use your tax-assessed value to estimate what your home would sell for—use it only to understand your property tax bill.

How to use your estimate once you have it

Once you know your home's approximate value, subtract what you still owe on your mortgage. That number is your home equity—the portion of the home you actually own. If your home is worth $400,000 and you owe $250,000, your equity is $150,000. This matters because you can borrow against equity through a home equity loan or line of credit, and it tells you how much you would walk away with if you sold and paid off the mortgage.

If you are thinking about selling, get a CMA from a local agent and use that as your baseline. If you are refinancing, your lender will order an appraisal, so you do not need to pay for one yourself. If you just want to know your net worth or understand your financial picture, an online estimate plus a free CMA from one agent will give you a reasonable range. Update your estimate every two to three years or whenever major changes happen in your neighborhood—a new highway, a school closure, or a wave of new construction can shift values quickly.

Frequently Asked Questions

Can I challenge my home's assessed value for taxes?

Yes. If you believe your assessed value is too high, you can file a formal appeal with your county assessor's office. The process and deadline vary by state, so check your county assessor's website for the specific steps and dates. You may need to provide evidence like a recent appraisal or comparable sales data.

Why is my Zillow estimate so different from what an agent told me?

Zillow's algorithm does not know the condition of your home, recent renovations, or neighborhood details an agent sees in person. An agent's estimate is based on actual recent sales of homes like yours, so it is usually more accurate. If estimates differ widely, a professional appraisal will settle the question, though it costs money.

Does the price I paid for my house affect what it is worth now?

No. Market value is determined by what buyers will pay today, not what you paid years ago. If you bought at $250,000 and the market has risen, your home is worth more. If the market has fallen, it is worth less, regardless of your purchase price.

How often should I get my home reappraised?

You only need a new appraisal when you are refinancing, taking out a home equity loan, or settling a legal matter. For general knowledge of your home's value, updating an online estimate once a year or checking a CMA every two to three years is enough.

What if my home is very new or very old—do estimates still work?

Online estimates work less reliably for very new homes (under one year old) or very old homes (over 100 years old) because there are fewer recent comparable sales. A CMA from a local agent or a professional appraisal is more accurate in these cases because the agent or appraiser can account for unique features and condition.