When you are in the midst of a divorce (even an amicable one), it can be significantly less painful for everyone to quickly get it over with. Unfortunately, many individuals are now turning to online appraisal services (such as Zillow), which can place a value on their home within a few minutes.

However, many disgruntled individuals are realizing that their homes are not worth quite what the “Zestimates” have to say. Buyers are having a hard time stomaching some of the numbers that the online appraisal sites are spouting— and for good reason. These services have plenty of pitfalls, which prevent them from producing an accurate appraisal of your marital home.

Even the founder isn’t immune to the inaccuracy.

Zillow CEO Spencer Rascoff recently sold his own home, and its final sale price came in significantly lower than his Zestimate. Given that Rascoff resided in a rather luxurious abode, his estimate was off by hundreds of thousands of dollars. That’s a steep discrepancy, which many homeowners could not afford to take in stride. Zillow valued his home at approximately $1.75 million, but the final sale closed at just $1.05 million—a 40% difference in price.

Why can’t online appraisals give you an accurate picture of the value of your marital home? Let’s take a look at the three most common pitfalls of online appraisal services.

1) Interior conditions are ignored.

The biggest reason that Zillow cannot accurately appraise your home is because it lacks the capacity to account for its interior condition. If you recently refurbished your kitchen or added all-new flooring, it is difficult to take those factors into consideration without seeing it. Likewise, if your walls are dingy and dented from abuse over the years, Zillow has no way of accurately deducting that from the overall value.

2) The margin of error is too high to be accurate.

The accuracy of Zillow’s Zestimate service is highly dependent on the information that the county has available regarding your property. When they are lacking basic information (e.g., the number of bedrooms or bathrooms, or the overall square footage), it makes it nearly impossible to calculate an accurate market value.

Zillow officially states that their national-median error rate hovers at around 7.9%. That makes a big difference when you are trying to divvy up your assets.

Unfortunately, based on their own statistics, certain cities are worse than others. To see how wide Zillow’s margin of error can be, take a look at these statistics:

• In Los Angeles, only 52.6% of homes sold within 5% of the Zestimate.
• In Santa Cruz, only 40.9% of homes sold within 5% of the Zestimate.
• In San Francisco, only 28.8% of homes sold within 5% of the Zestimate.

While it is clear that those odds are not great to begin with, consider what they mean in the grand scheme of home appraisals. If your home is worth $200,000, then you would be looking at a $10,000 margin of error each way—for an overall margin of $20,000. In cities where the accuracy of the Zestimates is abysmal (e.g., San Francisco), you are looking at a much wider margin of error.

Close to 20% of the homes sold in San Francisco have a margin of error of 20% or greater. In other words, there could be an $80,000 discrepancy on a $200,000 property.

3) Zillow may choose grossly inaccurate comps.

To accurately assess the value of your home, a professional appraisal service compares it to nearby sales of similar properties. A skilled appraiser would be able to identify whether these properties are similar to yours. Are they all townhomes? Are they in significantly different neighborhoods—with drastically different price ranges?

A local appraiser should know the area you live in well, but Zillow cannot always account for neighborhood boundaries. They also cannot always determine the difference in types of properties. Thus, a single-family dwelling may be compared to a townhome in their appraisals, which can drastically affect the value of your home.

You get what you pay for.

Here’s the bottom line: When you are looking to sell your marital home, you are better off hiring an actual appraiser. Then you can move on with your life. In-person appraisers can better account for the interior condition of your home. They have more accurate information regarding your property. And they can ultimately give you a more conclusive picture than Zillow can.

Think of Zillow as a reasonable starting point. It’s a way to find a wide range of approximate values for your home. It can be a great tool for comparing your appraiser’s values, and there is nothing wrong with asking additional questions. Just bear in mind that Zillow’s Zestimates are far more likely to be inaccurate than a professional appraiser’s opinion—after surveying your home and comparable properties.