Anyone looking to buy a home must assess their finances to ensure that they can balance their monthly mortgage payments with other expenses. According to a recent study by the real estate company RealtyTrac, this money management is easier to do when buying rather than renting in about three-quarters of the counties in the United States.

The company completed an analysis of properties purchased in the first quarter of 2015 to compare house payments on a median-priced home to the fair market monthly rent on a three-bedroom home. In 76 percent of the 461 counties included in the study, owning a home was the more affordable option.

"From a pure affordability standpoint, renters who have saved enough to make a 10 percent down payment are better off buying in the majority of markets across the country," said Daren Blomquist, vice president at RealtyTrac. "But factors other than affordability are keeping many renters from becoming buyers, a reality that means real estate investors buying residential properties as rentals still have the opportunity to make strong returns in many markets."

The analysis included 461 counties with a population of at least 100,000 and sufficient data on home prices, income, and rents. These counties had a combined population of 217 million people, or approximately 68 percent of the total U.S. population.

On average, monthly payments on a home required 24 percent of the estimated median income in the market. Rents represented 28 percent of this income.

Of the 461 counties included in the analysis, payments on a median-priced home were lower than fair market rents in 351 in the first quarter of the year. RealtyTrac says 56 of these counties saw home prices rise at least 7 percent from a year ago while wages rose at least 3 percent, factors the company says make homeownership especially attractive in these areas.

RealtyTrac named Bay County in Michigan and Fayette County in Pennsylvania as the areas where conditions are most favorable for buying. In each of these counties, 11 percent of the median household income would be required to make monthly payments on a median-priced home. Three other areas would require 14 percent of the median income to make these payments including Beaver County, Pennsylvania; Tazewell County, Illinois; and Butler County, Ohio.

The most affordable counties for renting were Delaware County, in the Columbus metro area of Ohio, and Williamson County, in the Nashville metro area of Tennessee. In each of these counties, the median rent on a three-bedroom property would require 14 percent of the median household income.

East Coast metro areas were the least affordable rental markets identified by the analysis. RealtyTrac says a three-bedroom property in Bronx County, New York, requires 69 percent of the median income for a monthly rent. This was followed by Baltimore City, Maryland (49 percent); Philadelphia County, Pennsylvania (48 percent); and Kings County/Brooklyn, N.Y. (48 percent).

The analysis also ranked counties based on the potential returns from investing in a residential rental property. The annual gross yield, or purchase price divided by the potential rental income, was 9.34 percent for rental properties purchased in February.

Baltimore City had the highest potential rental yield at 24.82 percent, followed by the Atlanta metro area of Clayton County, Georgia, at 24.26 percent. Wayne County, part of the Detroit metro area in Michigan, had the third highest potential yield at 21.08 percent.

The lowest potential rental yield was in Manhattan, N.Y., where the purchase of a rental property was calculated to have a return of only 2.34 percent. Other areas with low potential yields included San Francisco County, California, with 3.2 percent and Kings County/Brooklyn, N.Y., with 3.63 percent.

The average rental yield among all counties was down 42 basis points in February when compared to properties purchased a year ago. A basis point is defined as one one-hundredth of 1 percent.

A total of 115 counties had an increase in potential annual gross rental yields when compared to 2014. Fifty-eight of these counties also had rising rental rates, home prices, and average weekly wages.

Douglas County, Oregon, had the largest positive change from a year ago, with potential rental returns increasing 119 basis points. Linn County, Iowa, and Henderson County, North Carolina, each saw an increase of 109 basis points.

Monthly house payments used a baseline of a 10 percent down payment on a median-priced home with the payment including the costs for homeowner's insurance, mortgage insurance, and property taxes. RealtyTrac also used a 3.7 percent interest rate on a 30-year fixed mortgage as well as property tax and insurance costs totaling 1.39 percent of the sales price for a median-priced home. An additional 1 percent of the loan amount was also included to account for private mortgage insurance.

The analysis used the fair market rents that were set by the Department of Housing and Urban Development. Rental returns were based on HUD's figures for the county's average fair market rent for a three-bedroom home in the county. This rent cost was annualized and divided by the median sales price for a residential property in each of the counties.

Information on wages and unemployment rates was taken from the Bureau of Labor Statistics as well as the U.S. Census Bureau.