This is the detailed computation of the Net Investment Income Tax which is regulated by section 1411 of the Internal Revenue Code. We earlier published easy NIIT calculator. As you know, the net investment income of individuals, estates and trusts is taxed at the rate of 3.8% provided they have income above the statutory threshold amounts.
Net Investment Income Tax Calculator
Net Investment Income Threshold
Individuals will owe the tax if they have Net Investment Income and also have modified adjusted gross income over the following thresholds:
Filing Status Threshold Amount Married filing jointly $250,000 Married filing separately $125,000 Single $200,000 Head of household (with qualifying person) $200,000 Qualifying widow(er) with dependent child $250,000
It does not matter if an individual is exempt from Medicare taxes, he/she may still be subject to the Net Investment Income Tax if he/she has Net Investment Income along with MAGI in excess of thresholds( referred above).