Property Value: How to Look It Up, Verify It, and Trust the Number

"Property value" means three different things depending on who is asking. To a homeowner, it is the price a buyer would likely pay today. To a county tax assessor, it is a figure used to calculate your property tax bill. To a mortgage lender, it is the number a licensed appraiser signs off on before funding a loan. This guide walks through all three definitions, shows you how to look up each one for any address in the US, compares the five most-used free property value tools by accuracy and best use case, and explains when a free number is enough and when you need a binding valuation.

Key Takeaways

• Market value, assessed value, and appraised value are three different numbers for the same property. Assessed value is typically 60–100% of market value depending on your state and can lag market conditions by 1–3 years (NerdWallet, 2026).
• Free online property value tools (AVMs) carry median error rates of roughly 2% for on-market homes and 6–7.5% for off-market homes. On a $500,000 home, that is a $10,000–$37,500 spread (Bankrate, 2026; Clever Real Estate, 2025).
• The most reliable way to look up an assessed property value is your county tax assessor's public records portal — free, official, and the only source that reflects the number your property tax bill uses.
• Opendoor produces a binding cash offer on your address in 24 hours by combining AVM data with a condition assessment — the only free "property value" that carries actual purchase intent behind it (Opendoor).

What "Property Value" Actually Means

Property value is not one number. At minimum, it is three:

• Market value — what a willing buyer would pay a willing seller in an arm's-length transaction today.
• Assessed value — what your county tax assessor uses to calculate your annual property tax bill.
• Appraised value — what a state-licensed appraiser certifies for a specific transaction, usually a mortgage or refinance.

These three numbers describe the same physical property but rarely match. In California, a home with a market value of $900,000 can carry an assessed value of $300,000 because Proposition 13 caps assessment growth until the property changes hands. In a rapidly appreciating Sun Belt metro, a lender's appraised value can come in 5% below market because appraisers must lean on comparable sales from 60–90 days ago. Understanding which number you need — and which is showing up on the screen when you type your address into a free tool — is the difference between a decision that holds up and one that gets renegotiated.

The rest of this hub is organized around that question: which number do you need, where do you look it up, and how do you know the number you got is right?

Market Value vs. Assessed Value vs. Appraised Value

Every property carries at least these three valuations at any given time. They serve different audiences and update on different schedules.

Market value is what most homeowners mean when they say "property value." It reflects supply and demand today, in your specific ZIP code, for a home like yours. It moves with interest rates, local inventory, employment, and buyer sentiment. This is the number Zillow's Zestimate and Redfin's Estimate try to predict. It is also the number an Opendoor cash offer is anchored to, adjusted for condition and closing certainty. For a deeper breakdown of the concept, see fair market value.

Assessed value is a bureaucratic construct. Your county sets it on a fixed cadence to calculate what you owe in property tax. In most jurisdictions, assessed value is a fraction of market value — sometimes 60%, sometimes 100%, depending on state law and the local assessment ratio (NerdWallet, 2026). It also lags. If your county reassesses every three years, the number on your tax bill today may reflect a market that no longer exists. This is why Zillow's estimate and your tax assessment almost never match — and why one is not "wrong" relative to the other. They measure different things. For the mechanics of the county's number specifically, see what is a property tax assessment.

Appraised value is the number a lender trusts. A state-licensed appraiser visits the property, measures the square footage, evaluates condition, and compares your home against three to six recent verified sales within a half-mile radius. The final report is a legal document; it is what a mortgage or refinance decision is built on. Appraisals cost $300–$600 for a single-family home and are the standard for any transaction where a lender's capital is on the line (NAR). See home appraisal cost for a full breakdown.

For a side-by-side of the market versus appraised distinction specifically, see market value vs. appraised value.

How Property Value Is Calculated

Each of the three valuations uses a different methodology.

AVMs (automated valuation models) — the engines behind Zillow, Redfin, Realtor.com, Opendoor Estimator, Chase, and Bank of America — blend MLS sales records, county tax assessments, listing prices, days-on-market, and (for Zillow) homeowner-submitted updates through a proprietary algorithm (Bankrate, 2026). The math is essentially a weighted regression across comparable sales, with each tool weighting inputs differently. Redfin publishes that it uses 500+ data points (Redfin); Zillow relies heavily on user-updated home facts.

Mass appraisal for assessed value — county assessors do not visit every property. They use mass-appraisal models that price entire neighborhoods against a small sample of validated sales, then apply the local assessment ratio. This is why a recent kitchen remodel typically does not show up in your assessed value until a permit is pulled and reconciled — often years later.

Formal appraisal — a licensed appraiser uses one or more of three approaches:

• Sales comparison — the dominant method for single-family residential. The appraiser identifies three to six comps within a half-mile, adjusts for differences in size, condition, and features, and produces a value range.
• Cost approach — used for new construction and unique homes. Land value plus the cost to rebuild, minus depreciation.
• Income approach — used for rental and investment property. Value derived from expected rental income relative to local capitalization rates.

The sales comparison approach is why an appraised value hinges on which comparable sales the appraiser uses. In a thin market with few recent sales, appraisals become less reliable, and disputes between buyer, seller, and lender become more common.

How to Look Up Your Property's Value (Step-by-Step)

There are five ways to look up a property's value. In order of speed and use case:

1. Online AVM tools (30 seconds, free, ballpark). Type your address into Zillow, Redfin, Realtor.com, or the Opendoor Estimator. Each returns an instant market-value estimate. The Opendoor Estimator is the only one of the four that can be converted into a real cash offer with a single click — meaning the number is not just a prediction but a starting point for a binding transaction. For a broader walkthrough of the AVM options, see this home value estimate guide.

2. Your county tax assessor portal (free, official, for the assessed number). Every US county publishes property tax records online. Search by parcel number, address, or owner name. The record shows the assessed value, the assessment year, the tax bill, and often the sales history. Some states, including Kansas, offer a centralized statewide portal like the Kansas Property Valuation Express; most states require you to find the specific county assessor's site. If you are appealing your property taxes, this is where you start.

3. A comparative market analysis (CMA) from a local agent (free, more accurate than AVMs). A local real estate agent will pull three to six recent sales within a half-mile of your property, adjust for differences, and deliver a price range. It is typically 2–4 percentage points more accurate than a raw AVM because it incorporates condition adjustments. Agents provide CMAs for free because they hope to earn the listing. See our real estate comps guide for details on how agents build and read one.

4. A licensed appraisal ($300–$600, definitive). Order directly through a state-licensed appraiser. This is the number lenders will accept, and the number that carries weight in a divorce, estate, or tax appeal. Turnaround is typically 5–10 business days.

5. An Opendoor cash offer (free, binding, 24 hours). Enter your address on Opendoor, answer a short questionnaire about condition and features, and receive a preliminary cash offer within 24 hours. Unlike the four options above, the offer is a real number a real buyer will honor. It is the only "free property value" on the internet that pairs with actual purchase intent.

Which order to try them in. For a rough monthly check-in on your home's worth, use an AVM. For anything financial — insurance, refinance planning, tax appeal — pair the AVM number with the county assessor's number. For a decision that involves selling, get a CMA and an Opendoor offer to bracket the high (list-with-agent) and low-with-certainty (sell-to-Opendoor) ends of the range. For a lender, a court, or a formal negotiation, get an appraisal.

Comparing the Five Free Property Value Tools

The five most-searched free property value sources — Zillow Zestimate, Redfin Estimate, Realtor.com, Opendoor Estimator, and county tax assessor portals — behave very differently. Here they are side by side.

Sources: Clever Real Estate, 2025; Redfin; Bankrate, 2026.

The Zestimate vs. Redfin Estimate head-to-head — the two most-searched free tools. Redfin publishes a 2.09% median error rate for on-market homes and 6.47% for off-market (Redfin). Zillow's numbers, as measured by third parties, land at roughly 1.94% and 6.93% (Clever Real Estate, 2025). The tools are within a percentage point of each other on median. Where they diverge is coverage — Zillow's Zestimate is available for essentially every US address; Redfin's Estimate is strongest in markets where Redfin operates as a brokerage.

The Opendoor Estimator difference. Zillow, Redfin, and Realtor.com produce predictions. Opendoor produces a binding purchase offer. That is a categorically different product. A prediction is what an algorithm thinks a buyer might pay; an offer is what a buyer will actually pay, in cash, on a defined closing timeline. For how Opendoor's number is constructed, see how Opendoor calculates the value of your home.

Which Tool to Trust for Which Use Case

Different use cases call for different valuations. The decision matrix:

• Refinancing or applying for a HELOC. The lender will order an appraisal regardless of what an AVM says. Use the AVM to estimate whether you have enough equity to bother applying; use the appraisal for the actual decision.
• Setting a listing price. Average three AVMs, add a CMA from a local agent, and pull an Opendoor offer as the floor. The gap between the CMA high and the Opendoor offer is your "sell-fast-versus-sell-for-max" spread.
• Estimating equity. An AVM ballpark is fine at the application stage. The lender will formalize with an appraisal.
• Insurance coverage. Ask your insurer to base coverage on replacement cost, not market value. Land value is not what burns down.
• Property tax appeal. Pull the county assessor's number, then use two to three AVMs and (if the potential savings are large) a formal appraisal as counter-evidence. See our guide to what a property tax assessment is and how the number is derived.
• Divorce, estate, or bankruptcy settlement. Licensed appraisal. Courts do not accept Zestimates.
• Selling for a firm price in under a week. Opendoor cash offer.
• Casual monthly monitoring. Zillow's Zestimate updates weekly and is the lowest-effort option.

When Each Tool Is Wrong

Every property value source has failure modes. Knowing them is the difference between using a number and being fooled by it.

AVMs fail on unique properties. Rural homes with few nearby comps, custom architecture, historic homes, and freshly renovated interiors are all mis-priced by AVMs. Zillow's own methodology acknowledges that off-market accuracy degrades in low-density markets (Bankrate, 2026). If your home has a feature that is rare in your ZIP code — a large lot, waterfront access, a detached workshop, a recent gut renovation — the AVM number is likely low.

County assessments lag reality. If your county reassesses every three years, the tax number on file today reflects the market from up to three years ago. In appreciating markets, this means assessed value understates market value — sometimes dramatically. In declining markets, it can overstate.

Appraisals can come in low in fast-moving markets. Appraisers rely on comps that are typically 60–90 days old. In a market where prices are rising 1–2% per month, an appraisal can come in 3–5% below the contract price and force a renegotiation.

Cash offers price in certainty, not maximum sale price. An Opendoor offer is honest about the trade-off: you get speed, a chosen closing date, and no showings or repairs. That certainty carries a premium. If your priority is the highest possible number and you have 60+ days plus tolerance for uncertainty, listing with an agent typically nets more. If certainty is worth something to you — because you have already bought your next home, because you cannot afford two mortgages, because you are relocating for a job — the Opendoor offer prices that certainty into the number.

The single most useful habit: always compare at least two numbers from different methodologies. An AVM plus a CMA. An AVM plus an Opendoor offer. A county assessment plus an AVM. If the two numbers are within a few percent of each other, trust the range. If they diverge by more than 10%, something in the underlying data is off and it is worth investigating why.

Factors That Drive Property Value

Every valuation — AVM, assessment, appraisal, or cash offer — is built on the same underlying inputs:

• Location. School district ratings, walkability, crime, flood zone, commute times. Location is the single largest driver of value and the hardest one to change.
• Lot characteristics. Size, topography, waterfront or view, corner lot versus mid-block, easements.
• Structural fundamentals. Square footage, bedroom and bathroom counts, age, foundation type, roof age, HVAC age.
• Features and finishes. Kitchen and bathroom updates, hardwood floors, garage, basement finish, whether a pool adds value in your specific climate.
• Condition. The single input AVMs cannot see. A well-maintained home with an updated interior is worth 5–15% more than the same footprint in tired condition.
• Market factors. Mortgage rates, local employment, inventory levels, seasonality.

For a full breakdown, see factors that influence home value.

How to Increase Property Value

Not every dollar spent on a home returns a dollar of value. The highest-ROI improvements — the ones that consistently return most or all of their cost at resale — are surprisingly cheap.

The NAR 2024 Remodeling Impact Report ranks garage door replacement as the single highest-ROI project, with cost recovery around 194% (NAR). Other consistent winners:

• Minor kitchen remodel — refacing cabinets, upgraded hardware, new countertops, updated appliances. Typical cost recovery: 85–95%.
• Entry door replacement — steel front door with modern hardware. Cost recovery routinely above 100%.
• Hardwood floor refinishing — much cheaper than replacement and delivers strong buyer response.
• HVAC replacement (when the existing system is at end of life) — buyers discount homes with 15+ year-old systems significantly.
• Fresh neutral paint — the highest ROI per dollar of any single project.
• Curb appeal upgrades — landscaping, mulch, updated house numbers, front door hardware, power washing.

What does not pay back reliably: swimming pools in cold-climate markets, luxury kitchen or bath remodels that push the home above the neighborhood ceiling, and highly personalized finishes (dark accent walls, custom built-ins that only work for one lifestyle). Overimproving above the neighborhood ceiling is a well-documented trap — the market pays for a "$450,000 home in a $400,000 neighborhood" like a $410,000 home.

The general rule: cheap cosmetic upgrades and mechanical replacements return more than expensive additions. Do the paint, the landscaping, and the kitchen refresh before you consider the addition.

Tracking Property Value Changes Over Time

Property values move. Tracking them is useful for refinance timing, net worth planning, and property tax appeals. Four sources cover the full range:

• Zillow's monthly My Home dashboard — updated Zestimate for your specific address, plus a chart of value history. The fastest and lowest-friction option for property-level tracking.
• Redfin's owner dashboard — the same product from a different AVM. Cross-referencing both catches drift in either.
• Federal Housing Finance Agency (FHFA) House Price Index — quarterly index at the metro, state, and national level, based on repeat-sales data from conforming mortgages (FHFA HPI). US home prices have appreciated an average of roughly 4% per year since 1991 based on FHFA data, though averages hide enormous local variance.
• S&P CoreLogic Case-Shiller Home Price Indices — 20-city composite plus national index; the benchmark most economists cite (S&P CoreLogic Case-Shiller).
• Federal Reserve Economic Data (FRED) — free access to Case-Shiller, FHFA, and metro-level house price series (FRED house price series).

The most useful comparison for a homeowner: track your specific ZIP code Zestimate against the metro-level FHFA or Case-Shiller trend. If your home is appreciating slower than the metro, look at your condition and features. If it is outpacing the metro, either your specific neighborhood is a leader or something in the AVM data is off. For a deeper treatment of what drives long-term price growth, see factors that influence home value.

When to Get a Formal Appraisal Instead

Most homeowners never need to pay for a formal appraisal. The lender orders one during a mortgage or refinance and passes the cost through at closing. There are, however, a handful of situations where paying for one directly is worth it:

• Property tax appeal on a higher-value home. A $500 appraisal is worth it if it saves $2,000 per year in property taxes. On a lower-value home where the potential savings are $200, it usually is not.
• Divorce settlement. Courts require a neutral valuation. Zestimates do not qualify.
• Estate settlement. IRS "date of death" valuations for stepped-up basis require an appraisal; AVMs are not accepted.
• Pre-listing pricing on unique properties. Historic homes, custom builds, waterfront, or homes on unusual lots benefit from a professional opinion because AVMs are systematically wrong on outliers.
• PMI removal. Some lenders will drop private mortgage insurance based on a new appraisal showing the loan-to-value ratio has crossed 80%.
• Bankruptcy or creditor proceedings. As with divorce, courts require professional valuations.

Expect to pay $300–$600 for a single-family home appraisal; $500–$900 for multi-family, unique properties, or rural homes with sparse comps. See home appraisal cost for a full breakdown.

The Opendoor Cash Offer as a Ground-Truth Signal

Every AVM on this page produces a prediction. Opendoor produces an offer.

That distinction matters even for homeowners who are not selling. An Opendoor cash offer is a binding number backed by capital and standardized to a specific closing timeline. It is the only free property value on the internet that a real buyer would actually honor. That makes it a useful "second opinion" data point — a floor number that carries actual purchase intent behind it, which no Zestimate or Redfin Estimate does.

Opendoor's number is built by combining AVM data (the same comp-driven regression the other tools use) with a condition assessment specific to your property. The result is adjusted for the certainty premium: you know the number, the closing date, and the terms up front, with no showings, no financing contingencies, and no back-and-forth. For a homeowner comparing sources, that certainty is what makes the Opendoor offer distinct from an AVM prediction. See how Opendoor calculates the value of your home for the full methodology, or get a free property value estimate from Opendoor if you want to see the number on your specific address.

The honest trade-off: if maximum sale price is your priority and you have 60+ days, listing with an agent typically nets more. If certainty, speed, and simplicity are the priorities — because you have already bought your next home, are relocating, or need to avoid two mortgage payments — an Opendoor offer is a defensible price floor.

Common Inaccuracies and Red Flags

Signals that your AVM number is wrong or off:

1. Recent improvements not on public records. If you pulled permits for a kitchen or bathroom remodel in the last 6–18 months, the AVM likely has not caught up. Update your home facts on Zillow and Redfin directly. On Opendoor, you can update details as part of the offer flow — and Opendoor recalculates the preliminary offer based on the corrected information before final assessment (Opendoor support).
2. Distress sales in the comp set. If foreclosures, tear-downs, or off-market family transfers show up in the nearby recent sales, the AVM will over-weight them. This is especially common in slower markets and after natural disasters.
3. Uniqueness. Historic homes, waterfront, custom architecture, and unusual lot sizes all break AVMs. If your home is the only one of its kind on the block, get a CMA or an appraisal — do not trust the free tool.
4. Recent tax reassessment. A sudden jump in assessed value creates a step-change that some AVMs interpret as a market signal. If your county just reassessed and the AVM number spiked, wait a cycle before treating it as fresh data.
5. Recent subdivision or lot combination. If the parcel was split or combined, the AVM may still be pricing the old configuration.

How to correct wrong data. For property tax records, contact your county assessor directly and follow the appeal process — start with what a property tax assessment is and your county's published appeal deadlines. For Zillow and Redfin, log in and submit updated home facts through the owner dashboard. For Opendoor, provide the correct details during the offer flow, or contact Opendoor support at 888-352-7075 or support@opendoor.com to update your home's information; the preliminary offer will be recalculated (Opendoor support). If your property is showing on a listing site with inaccurate details and you would prefer it not appear at all, Opendoor lets sellers remove their home from its site (Opendoor support).

The pattern to watch for: any single number that diverges by more than 10% from the others is not a discovery — it is a data problem to investigate. Reconcile it before making a decision on it.