Also, Utahns buying non-employer-based health insurance on their own would pay twice as much under Romney's plan as they would under Obama's: $13,781, compared to $6,566 in 2016.
And 70,000 fewer middle-income families would receive tax breaks to pay for coverage.
The report, which uses economic modeling based on U.S. Census and other data, paints a similar picture nationally.
It was written by the policy experts who advised then-Gov. Romney on the overhaul that gave rise to federal health reform: MIT economics professor Jonathan Gruber; Stuart Altman, a professor at Brandeis University; and John McDonough, professor and director of the Harvard School of Public Health's Center for Public Health Leadership.
The findings were panned as "fatally flawed" by conservatives such as Avik Roy, a contributing columnist to Forbes.
The report glosses over the taxes and Medicare cuts used to pay for Obama's health overhaul, Roy argues. And it makes no mention of previous analyses by Gruber showing "Obamacare would dramatically increase insurance premiums … due to its regulations and mandates that would not be part of Romney's plan," he wrote.
Gruber admitted that any modeling exercise has limitations, especially when it comes to predicting how imprecise campaign promises will materialize.
"If anyone is going to criticize us it will be for taking on the task, as opposed to taking it on faith that RomneyCandidateCare will work," he said.
Gruber examined how health reform compares to the Massachusetts law, if it were superimposed on every state.
"You get pretty much the same thing, the same amount of uninsured are covered and the same number of people get tax credits to buy coverage on their own," he said. "The only difference is tax credits under RomneyCare are more generous."
Romney's new plan, however, would give fewer people tax breaks, and they wouldn't be as generous, the report shows.
The candidates on health care
Both presidential candidates vow to reduce health spending, but in different ways:
Obama • The president's signature health overhaul would insure more low- and middle-income families by expanding Medicaid and subsidizing the purchase of coverage on health insurance exchanges. It protects consumers by barring insurers from denying coverage to sick people, and from charging them more.
The law is funded, in part, by reducing Medicare payments to doctors, hospitals, drug companies and medical device makers, which is supposed to be offset by the money they'll make from newly insured Americans.
Romney • The Republican challenger calls for loosening regulations on insurers to ensure greater consumer choice, and would offer states more flexibility by turning Medicaid into a block grant program.
He supports guaranteed coverage for people with pre-existing conditions but only for those who maintain their coverage. He wants to allow people to purchase insurance across state lines.
He hasn't said how he would cut Medicare spending, but has publicly supported his running mate Paul Ryan's plan to turn Medicare into a voucher program.