Healthy consumers could see insurance rates double or even triple when they look for individual coverage under the federal health law later this year, while the premiums paid by sicker people are set to become more affordable, according to a Wall Street Journal analysis of coverage to be sold on the law's new exchanges.

The exchanges, the centerpiece of President Barack Obama's health-care law, look likely to offer few if any of the cut-rate policies that healthy people can now buy, according to the Journal's analysis. At the same time, the top prices look to be within reach for many people who previously faced sky-high premiums because of chronic illnesses or who couldn't buy insurance at all.

Several big provisions in the law taking effect in six months affect rates for the estimated 20% of Americans who don't have coverage through an employer, Medicare or Medicaid. Plans must be available to consumers regardless of their health and must cover certain items such as hospitalization, maternity care and prescription drugs. The exchanges are set to open Oct. 1 selling plans effective Jan. 1.

A review of rates proposed by carriers in eight states shows the likely boundaries for the least-expensive and most costly plans on the exchanges. The lower boundary is particularly important because the government wants to attract healthy people to the exchanges, and they may choose to pay a penalty and take the risk of going without coverage if they believe they can't get an acceptable deal

For a 40-year-old single nonsmoker—in the middle of the age range eligible for exchanges—a "bronze" plan covering about 60% of medical costs will be available for about $200 a month in most places, the proposals show.