Real estate websites and their mobile siblings are indispensable tools, whether you’re a serious homebuyer, you’re thinking of selling, or you’re just curious about what your neighbors pay in taxes. You can get a sense of how much your home is worth, and arrange for regular updates when properties in communities of your choosing are listed or have a price change.

Three of the real estate websites we’ve researched here—Realtor.comTrulia, and Zillow—are portals; they get their information from regional multiple-­listing services (MLSs), ­databases of properties shared by agents and brokers. (Since February 2015, Trulia has been owned by Zillow’s parent company.) A fourth service, Redfin, is not a portal, though you can use it like one to list, search for, and view properties. It works as a real estate brokerage. If you list with Redfin, your property is posted on MLSs and shared by the portals.




All four real estate websites provide the same baseline property information. They allow you to filter searches in a community by price range, and number of bedrooms and baths. You can save and share a listing, and arrange for regular updates on particular searches.

All of the services are free. Because not all MLSs participate with any one site, none of the sites provides a complete picture of what’s currently on the market. So we recommend that you try them all. But because time is valuable, here we’ve pointed out unique and potentially useful features—and drawbacks—for each site.

One tip: Exercise skepticism when using price-valuation tools on real estate websites. Redfin, Trulia, and Zillow can value your home when you type in your address. But we found that the estimates can vary wildly and may not be a reliable prediction of what you’d get if you sold. In a study, Zillow researchers compared selling prices of homes on its database with their original estimates. A third of homes sold at a price within 5 percent of their “Zestimates,” indicating a very accurate valuation; most were further from the mark. For more accuracy, ask a real estate agent for a free, comparative market analysis.

Realtor.com

Coverage: Every state and D.C.

App: For iPhone, iPad, and iPod Touch (iOS 8.0 or higher); Android (versions vary by device). Realtor Express app is available for iOS 9.

Updates data: 90 percent of listings are updated every 15 minutes; the rest are updated daily.

Unique features: Sponsored by the National Association of Realtors. Users have access to almost 800 MLSs nationwide. The website’s “Request Renovation Report” feature provides home-renovation information gleaned from public records. A new mobile app for iOS 9 has a 3D “flyover” feature for certain areas.

What we liked: You can easily check property records­ for every house on a street. Property pages prominently list upcoming open houses. Local market data is clear and useful. Realtor.com’s mobile app lets you use your fingertip to outline the area you want to focus on and search for homes by school district.

Negatives: Online home search tool was not as robust as those of Redfin and Trulia. For example, it has no for-sale-by-owner listings. A representative told us that a few features would be added in early 2016, including the age of the home, search in nearby cities, additional features such as swimming pools and waterfront properties, and the ability to hide certain kinds of listings, such as pending listings.

Redfin

Coverage: 75 metropolitan areas. Not in AL, AK, CT, DE, IA, ID, KS, MS, ND, SD, WV, or WY; in MN only in Minneapolis-St. Paul.

App: For iPhone and iPod Touch (iOS 7.0 or higher); Android (4.1 or higher).

Updates data: Every 15 to 30 minutes.

Unique features: Home shoppers who want to view a home in person are connected with a salaried Redfin buyer’s agent. If you buy with the agent, Redfin pays you a rebate based on the home price.* If you use Redfin, your total cost is a 4 to 4.5 percent commission, a discount from the 5 or 6 percent traditional in many places. “Last Call” option informs you when competing buyers weigh in with bids so that you can counter. In markets it serves, it offers free homebuying classes.

What we liked: Home search tool is fairly robust; among other features, you can specify fixer-uppers, waterfront homes, and homes with views. If a house you covet is not for sale, type its address and “favorite” it; Redfin will send an alert if it gets listed. With “Price Whisperer,” a potential seller can upload his home’s photos and set a potential selling price with a Redfin agent; the agent then polls up to 250 buyers in the area, asking whether they would buy at that price, and reports the results.

Negatives: Even within states where it operates, Redfin doesn’t participate in every MLS.

Trulia

Coverage: More than 350 MLSs nationwide.

App for iPhone, iPad, and Pod Touch (iOS 8 or later; optimized for all iPhone 6 devices); Apple Watch; Android and Android Wear watch (versions vary by device).

Updates data: Every 15 minutes.

Unique features: Focuses on an area’s lifestyle factors, including proximity of particular stores, restaurants, and cafes, as well as crime statistics. You can set a commute time by auto or public transportation to a specific location; the search tool identifies properties with commute times that fit those parameters. When you’re on the move, you can use the Apple and Android apps to identify nearby open houses that are in progress or about to start.

What we liked: A “walk score” assesses how easy it is to do errands on foot from the home. The site offers deep demographic data, such as where single people in the area live or the prevalence of college-educated residents around a given property. You can limit your search to a particular school district.

Negatives: In some cases, Trulia won’t provide a home-value estimate until you agree to have your contact information sent to a real estate agent.*

Zillow

Coverage: More than 350 MLSs nationwide.

App: For iPhone, iPad, and iPod Touch (7.0 or higher); Apple Watch; Android and Android Wear watch (versions vary by device).

Updates data: Every 15 minutes.

Unique features: Provides deep analytics and data on individual properties and municipalities, including historical trends. Zillow’s Home Value Forecast, for instance, crunches local properties’ Zestimates­­ to project whether local prices will rise, fall, or flatten. Provides a nationwide real estate agent directory that shows how many recent deals each agent has done, as well as customer reviews.

What we liked: A “Price This Home” feature lets potential sellers claim their property on Zillow and select their own “comps”—nearby properties that have recently sold—to create their own private price estimate that’s not published on the site. That way, they can take into account local features that the Zestimate algorithm might not have taken into consideration. “Walk score” similar to Trulia’s assesses how easy it is to do errands on foot from the home.

Negatives: Online search tool not as robust as those of Trulia or Redfin.

*Corrections: An earlier version of this article suggested that Trulia will not provide a home-value estimate until you agree to have your contact information sent to a real estate agent.

The earlier version of this article also said that the Redfin buyer rebate was based in part on the results of a satisfaction survey.

This article also appeared in the March 2016 issue of Consumer Reports magazine.