The tax filing threshold is the most income you can have and not be required to file a tax return.
For 2018, the tax filing threshold is $12,000 for an individual and $24,000 for a married couple.
If you don’t have health insurance in 2018, the penalty is $695 per adult plus $347.50 per child (up to $2,085 total) or 2.5% of income above the tax filing threshold, whichever is more.
People with very high incomes will pay the maximum penalty. The maximum penalty is the national average cost of a bronze health insurance plan. We don’t know this number for 2018 yet. For 2017, it was $272 per month (or $3,264 per year) for each person. Families larger than five people have the same maximum as a family of five.
If you have insurance for part of the year, you divide the amount for the whole year by 12 to get the monthly penalty amount. Count the number of months you didn’t have insurance and multiply the monthly penalty by that number. For example, if you didn’t have insurance for 8 months and the annual penalty is $695, you will owe $695 divided by 12 times 8, or $463.