Now that the minimum coverage provision (i.e., the mandate) in the Affordable Care Act has been upheld as constitutional several outlets have been explaining exactly who would be affected. For my part here are three charts showing how many people might be affected, at what income levels they would be exempt, and a flowchart for how the whole thing works.
(Source: Kaiser Fast Facts)
(Source: Kaiser Health Reform)
(Source: Surprise, Kaiser Health Reform)
For further nuance on who would be affected I recommend the Urban Institute’s estimate (PDF) (my emphasis in bold):
About 7.3 million people—2 percent of the total population (3 percent of the population under age 65)—are not offered any financial assistance under the ACA and will be subject to penalties if they do not obtain coverage.
Lastly, here (PDF) is the Congressional Budget Office’s revised update for coverage (my various emphasis in bold):
Compared with prior law, the ACA is now estimated by CBO and JCT to reduce the number of nonelderly people without health insurance coverage by 30 million to 33 million in 2016 and subsequent years, leaving 26 million to 27 million nonelderly residents uninsured in those years (see Table 3, at the end of this report). The share of legal nonelderly residents with insurance is projected to rise from 82 percent in 2012 to 93 percent by 2022. According to the current estimates, from 2016 on, between 20 million and 23 million people will receive coverage through the new insurance exchanges, and 16 million to 17 million people will be enrolled in Medicaid and CHIP. Also, 3 million to 5 million fewer people will have coverage through an employer compared with the number under prior law.
Bonus link: Kaiser’s subsidy calculator helps you estimate where you’ll fall on the ACA spectrum.