Finding the right NYC apartment to buy is as much about a careful numbers analysis as it is cruising dreamy, well-lit listing photos. To help suss out whether or not a potential apartment is a smart investment, you may want to check out the data in the listings at RealtyHop—a new sales-focused website from the folks behind RentHop.

The site offers the usual details—the number of bedrooms, the state of the kitchen appliances, etc.—along with every property’s estimated investment potential if you were to  rent the place out. Called a cap rate, this number represents the annual operating profit—which is the estimated rental income minus yearly expenses and common charges, divided by the asking price.

(A few things to keep in mind if you're thinking of going the investment property route: since many co-ops limit sublets or forbid them completely, this cap rate analysis is more relevant if you’re looking for a condo. RealtyHop's estimated rental income is based on the asking rents of comparable properties in the area, assumes 100% occupancy, and doesn’t take into consideration things such as the cost of repairs, advertising, closing costs or sublet fees paid to the board.)

In this week’s round-up, check out a 3,100-square-foot Flatiron loft, an alcove studio in Battery Park City, and a whisper-quiet Tribeca two-bedroom that faces an interior courtyard. All have estimated cap rates of between two and four percent, which makes them solid investments according to RealtyHop.

Two-bedroom, 2-bath  Carroll Gardens condo at 49 Summit Street, #2C for $1,500,000

This 1,357-square-foot condo offers a south-facing wall of windows, 10-foot ceilings, a walk-in closet in the master bedroom, a large in-unit storage room that houses a washer and dryer, as well as a separate storage space outside the apartment. The Carroll Gardens condo is listed for $1,500,000 (cash only). Maintenance is $276 a month, taxes are $183 a month, and the estimated cap rate is 3.17%.

Two-bedroom, 2-bath Flatiron District condo at 108 Fifth Ave, #11A for $2,200,000

Another Flatiron option: this 1,100-square-foot condo located just a short walk from the Union Square Farmers Market. It's outfitted with a stacked washer and dryer, a wine cooler, a number of large closets, and a private balcony that can fit a small table and chairs. Amenities include a 24-hour doorman, a live-in super and a recently renovated lobby. The apartment is occupied through August 31, 2016. Maintenance is $1,395 a month, taxes are $1,316, and the estimated cap rate is 2.54%.

One Bath Battery Park City studio at 333 Rector Place, #1106, for $798,000

This alcove studioin Battery Park City has a wall of windows, a large open kitchen with stainless steel appliances, and in-unit laundry. The building offers a state-of-the-art fitness center, a playroom, a business center and a lounge. Asking price is $798,000, Maintenance is $735 a month, taxes are $728, and the estimated cap rate is 2.54%.

Three-bedroom, three-bath Flatiron District co-op at 105 Fifth Avenue Apt #9A for $4.75 million

This 3,100-square-foot co-op in the Flatiron District features nine large windows, professional-grade kitchen appliances, a home office, and a laundry closet (in addition to a separate laundry room in the building). Building amenities include a virtual doorman, a super who accepts packages, and a shared storage area. Monthly maintenance is $4,940 and the estimated cap rate is 2.67%.

Two-bedroom, 2-bath Tribeca condo at 25 Murray Street, #8E for $1,995,000

This 1,127-square-foot condo features 11-foot ceilings, a stainless steel kitchen and great closet space. And even though it’s located in bustling Tribeca, it faces into an interior courtyard, so it’s super quiet. The pre-war building has modern amenities, including a doorman, a live-in super, a newly renovated gym with a sauna, a children’s playroom, a bike room and a furnished roof deck. The condo is listed for $1,995,000 (cash only). Maintenance is $785 a month, taxes are $1,236, and the estimated cap rate is 2.56%.

RealtyHop is a search engine for NYC apartment buyers looking for undervalued or great investment properties. RealtyHop listings include estimated investment potential in the form of a cap rate: a calculation derived from the annual operating profit divided by the purchase price.

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