Counselors Amelia Kupchyk, left, and Vanessa Gomez help clients with computer work required to navigate the second round of open enrollment at the Greater Prince William Community Health Center in Manassas, Va., on Nov. 15. (Linda Davidson/The Washington Post)

People shopping on the HealthCare.gov marketplace that reopened Saturday have more options this year than they did last year, but the options usually will be costlier.

Twenty-five states using the federal enrollment portal on average have higher premiums this year for the most popular level of health insurance plans — called “silver” plans — while nine states on average have lower prices this year for that level of coverage, according to a Washington Post analysis of federal data. New plans are typically slightly more expensive than existing ones, the analysis showed.

The calculations represent rough brushstrokes. Premiums can vary widely by state and county, reflecting the varying competitive situations facing insurers in different markets. Prices also differ based on the level of coverage purchased, family size, a customer’s age and tobacco use.

People who previously bought insurance through the federally managed Web site will be automatically enrolled in the same plan or a similar one if they don’t take action to change their coverage. Those consumers face an average price increase of 7 percent, or about $34 per month.

The Post’s analysis is based on a massive data file of premiums that federal health officials released Friday, about 12 hours before the Affordable Care Act insurance marketplaces opened for business. The premiums listed don’t take into account the sizable subsidies for which most consumers qualify. (Last year, subsidies reduced the average cost of a monthly premium to $82 for the 87 percent of shoppers on the federal exchange who received the financial assistance, according to the Department of Health and Human Services.)

In a broad summary of the most popular ”Silver” level plans across each state in the federal exchange, 25 states had premium increases and nine states had declines in the new exchange that opened Saturday, according to an analysis by The Washington Post.

The Obama administration is encouraging people who bought coverage last year to shop in the marketplace for a better deal. Many more plans were added this year than dropped, according to the data released by the administration. The data do not include the 16 states, plus the District of Columbia, that are running their own insurance marketplaces.

Price increases were largest for the most expensive plans, called “platinum” plans, sold on the marketplaces, according to the Post analysis. Premiums for the typical existing platinum plans rose 15 percent, or $111. Premiums for the less expensive silver and bronze plans rose 7 percent, or $34 and $27, respectively.

The plans that provide less coverage often come with higher out-of-pocket costs, in the form of co-pays and deductibles. The ACA also allows insurers to charge smokers more and to charge the oldest enrollees three times as much as the youngest.

Most shoppers last year bought silver-level plans, which cover 70 percent of a person’s medical costs. Alaska shows the highest year-over-year increase in silver plan prices for any state on HealthCare.gov, with premiums rising $301, or 32 percent. Nebraska had the second-largest dollar increase: $105, a 17 percent jump.

South Dakota and Mississippi had the biggest drops in the premium of the typical silver plan. South Dakota’s dropped 18 percent, or $142, to $642, while Mississippi’s went down 15 percent, or $119, to $693.

Outside analyses by health-policy consultants show wide variations in what people may pay. Avalere Health found that bronze plans, which cover 60 percent of a person’s medical costs, will increase an average 3 percent across the country for a 50-year-old nonsmoker. But the average price would increase 28 percent this year if that person lived in Alaska, while it would decrease 19 percent for someone living in Missouri.

In releasing the information, federal health officials did not comment on the shift in prices. Instead, they focused on an expansion in health plans that will be sold through the federal marketplace in many parts of the country. Overall, 90 percent of consumers shopping for coverage through HealthCare.gov will have a choice of at least three health plans — compared with about 75 percent of such consumers during the ACA’s first enrollment period.

President Obama encouraged Americans to take advantage of open enrollment for the Affordable Care Act in his weekly address on Saturday. (Reuters)

Amy Goldstein contributed to this report.