Valuation · 8 min read
Home appraisal vs. online valuation
What an appraisal, a CMA, and an online estimate each actually measure, who produces them, and which one you need for selling, refinancing, taxes, or plain curiosity.
Updated July 31, 2026
The short answer: an appraisal is a licensed professional's defensible opinion of your home's value on a specific date, a CMA is an agent's pricing analysis for a listing, and an online valuation is a statistical estimate from a model. All three are built on the same raw material, recent comparable sales, but they answer different questions and carry different weight. Nobody would use an online estimate to settle an estate, and nobody needs a paid appraisal to satisfy casual curiosity.
What is a home appraisal?
A home appraisal is a written opinion of market value prepared by a state-licensed or state-certified appraiser, following the Uniform Standards of Professional Appraisal Practice (USPAP) published by The Appraisal Foundation. The appraiser inspects the property, measures and photographs it, selects comparable recent sales, adjusts them for differences, and defends a single number in a signed report.
Appraisals exist because lenders need an independent check before funding a mortgage, and because courts, the IRS, and tax authorities need a value that can survive scrutiny. The report typically costs a few hundred dollars and takes days to weeks. One honesty note: Home Value Pros does not perform appraisals and is not a licensed appraiser. We publish online valuations, which are a different product entirely, described below.
What is a comparative market analysis (CMA)?
A CMA is a pricing analysis a real estate agent prepares, usually free, to recommend a list price or evaluate an offer. The agent picks comparable sales the way an appraiser would, but the goal is strategy, not a defensible value: where to price so the home sells well in your market right now.
The National Association of Realtors trains and encourages agents to produce CMAs as part of listing work, and a good one from a local agent is genuinely useful. Its limits: it is not performed under USPAP, it carries no weight with a lender or a court, and its quality depends entirely on the agent's skill and honesty. An agent who wants your listing may shade the number high.
What is an online valuation (AVM)?
An online valuation comes from an automated valuation model, or AVM: software that compares your home's recorded facts against thousands of recent nearby sales and market trends, then produces an estimated value or range. Zillow's Zestimate, Redfin's estimate, and our own valuation at Home Value Pros are all AVMs. They are instant, free, and available for nearly every home in the country.
The trade-off is that no one visits your house. An AVM does not know you renovated the kitchen, that the roof is at end of life, or that your lot backs to a busy road. It is the right tool for a fast, honest ballpark and for tracking your market over time. It is the wrong tool for anything that requires a number you can defend to a lender, a court, or the IRS.
Which one do you need?
Match the tool to the decision. The rule of thumb: the higher the stakes and the more formal the audience, the more human the valuation needs to be.
- Selling and setting a list price: start with an AVM for the ballpark, then get CMAs from two or three local agents. That combination is what most successful sellers actually use.
- Refinancing or a HELOC: the lender orders the appraisal and only that number counts. Use an AVM beforehand to sanity-check whether the refi math works.
- Estate settlement, divorce, or date-of-death value: hire a licensed appraiser. These need a USPAP report, and an online estimate will not be accepted.
- Property tax appeal: an independent appraisal is the strongest evidence, though a well-documented set of comparable sales can be enough in many jurisdictions.
- Curiosity or early planning: an AVM is the right tool. Watch the trend over months more than any single number.
How do comps drive all three?
Comparable sales are the shared foundation. Every valuation method for a typical home starts from the same question: what have similar nearby homes actually sold for recently? The methods differ in who picks the comps and how differences are handled.
An appraiser hand-selects a few comps and adjusts each one line by line for size, condition, lot, and features. An agent does a looser version tuned to buyer psychology. An AVM blends far more sales data than a human could hold, which makes it strong on typical homes and weaker on unusual properties or thin markets where one odd sale bends the model. The Federal Housing Finance Agency tracks appraisal and AVM performance for exactly this reason: comp quality is where every valuation lives or dies.
How accurate should you expect each to be?
An appraisal is the most careful number, but it is still one professional's opinion. Two competent appraisers can land a few percent apart on the same house. A CMA is accurate in the hands of a skilled, honest agent and useless from one who is buying your listing with a flattering price. A well-tuned AVM in a normal market typically lands within about 5 to 8 percent of the eventual sale price for standard homes, and much wider for unusual ones.
How do you prepare for an appraisal?
You cannot change your home's location or size, but you can make sure the appraiser sees everything that supports value. Preparation is mostly documentation plus basic maintenance.
- A list of improvements with dates and costs: roof, HVAC, water heater, kitchen and bath work, additions. Receipts and permits where you have them.
- Permits for any permitted work, especially additions and conversions. Unpermitted space may not count as living area.
- A recent survey or plat if you have one, plus HOA documents for condos and planned communities.
- Access to everything: attic, crawl space, garage, outbuildings, electrical panel.
- Small repairs done: dripping faucets, cracked panes, dead smoke detectors, peeling exterior paint. Minor deferred maintenance reads as overall condition.
Deep cleaning is not required; appraisers value condition, not tidiness. But a maintained, uncluttered home is easier to inspect and leaves no ambiguity about what is wear versus what is mess. If you are still months from a formal appraisal, start with your address: a free online valuation gives you the range, and you will know whether a paid appraisal is worth ordering at all.
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