Federal Poverty level. https://aspe.hhs.gov/2017-poverty-guidelines#threshholds
1. Non-expansion medicaid state (usually red states)
Income < 100% federal poverty level => Medicaid.
Income > 100% poverty level but < 400% of poverty level => ObamaCare with subsidy
Income > 400% poverty level => Obama Care without subsidy.
2. In blue states (CA, NY etc)
the 100% federal poverty level is increased to 138% federal poverty level.
So if your come is < 138% of FPL, you go to medicaid.
etc. etc.
