How self-employment tax works
Self-employment tax is the self-employed version of the Social Security and Medicare taxes an employer would otherwise split with you. The combined rate is 15.3%.
It applies to 92.35% of your net profit: 12.4% for Social Security up to the $176,100 wage base, plus 2.9% for Medicare with no cap.
This part is federal and the same in every state, including Massachusetts.
The Massachusetts income tax piece
On top of SE tax, Massachusetts charges state income tax on your profit. Half of your SE tax is deductible first, which this calculator applies before computing the state tax.
That makes your total tax the federal SE tax plus the MA state income tax — the combined figure shown above.
What this does and doesn't include
This estimate covers self-employment tax and Massachusetts state income tax. It does not include federal income tax, the qualified business income (QBI) deduction, or the extra 0.9% Medicare tax on high earners.
Treat it as a planning baseline for setting aside money for quarterly taxes, and verify with the Massachusetts Department of Revenue (mass.gov/dor) or a tax professional.
Frequently asked questions
How much is self-employment tax?
It is 15.3% of 92.35% of your net profit — 12.4% Social Security up to $176,100 and 2.9% Medicare. This part is federal and the same in Massachusetts.
Do I pay Massachusetts state tax on self-employment income?
Yes — Massachusetts taxes your net profit at its state income tax rate, on top of federal self-employment tax.
Is half of self-employment tax deductible?
Yes. You can deduct half of your self-employment tax when calculating income tax, which this calculator applies before the state tax.
Does this include federal income tax?
No. It shows self-employment tax plus MA state income tax. Federal income tax is separate and depends on your full return.