Millennials, what are you waiting for? You should be buying a home right now. That’s the conclusion of a pair of recent studies that looked at homeownership.

Zillow, the online real estate website, considered how rising interest rates and home price appreciation would affect a buyer’s ability to purchase a home. Even though interest rates have been hovering at yearly lows, most observers expect them to begin rising soon. Home values have been steadily climbing for some time.

Assuming that home values stayed constant and that a homebuyer would put 20 percent down and take out a 30-year fixed-rate mortgage, Zillow found that a D.C.-area buyer, for example, who waits one year to purchase a home would probably pay an additional $186 per month.

According to Erin Lantz, vice president of mortgages at Zillow, the rule of thumb is that a 1-percentage-point increase in mortgage rates decreases affordability by 10 percent.

Meanwhile, the Harvard Joint Center for Housing Studies wondered why first-time homebuyers were staying out of the housing market, especially now that home affordability was near an all-time high.

The center focused on 25- to 34-year-olds, the group most likely to become first-time home buyers, to find out how many earned enough to afford a median-priced home in the top metro areas. It discovered that in 42 of the 85 metro areas, more than half of the renters can afford the monthly costs of homeownership.

The median home is considered affordable if mortgage payments — with a 5 percent down payment, typical of first-time buyers — property taxes, insurance and nonhousing debt payments make up no more than 43 percent of a household’s income.