The complete guide
Michigan self-employment tax calculator: how it works
Self-employed? You pay the employee AND employer share of FICA — 15.3% of your net profit — plus federal, Michigan’s 4.25%, and city income tax. See your full tax picture.
When you’re self-employed in Michigan, there’s no employer splitting FICA with you — you pay the whole 15.3% (Social Security and Medicare combined) yourself. Then, on top, you owe federal income tax, Michigan’s flat 4.25%, and city income tax if applicable. This calculator runs your net profit through all of it, including the half-of-SE-tax deduction the law gives you.
How self-employment tax works
You owe SE tax on your net self-employment profit, but only on 92.35% of it (the law lets you skip the employer half of the Social Security "matching" on the amount that would have been the employer’s). The rate is 15.3% — 12.4% Social Security up to the $184,500 wage base plus 2.9% Medicare, with an extra 0.9% Medicare surtax once your income passes $200,000. Unlike employees, you pay this as an annual tax through quarterly estimated payments.
The half-SE-tax deduction
You get to deduct half of your SE tax — effectively the "employer" half — from your income before computing federal income tax. That means your federal and Michigan taxable income are reduced by that amount. The calculator applies this automatically, so the federal and state lines you see are the real ones, not the naive figure.
Michigan’s 4.25% on self-employment income
Your net self-employment profit flows into your federal AGI and then into your Michigan taxable income after the $5,900 exemption. The flat 4.25% applies to whatever’s left. If you’re a resident of a taxing city — say Detroit — the city’s 2.4% applies to your self-employment income too, paid through your city estimated payments.
Quarterly estimated payments
Since nothing is withheld, the IRS and Michigan expect you to pay quarterly — the federal deadlines are roughly April 15, June 15, September 15, and January 15 of the next year, with Michigan mirroring that calendar. The annual figures this calculator gives you are what your estimates should add up to. Use them to split each quarter’s payment.
The $100,000 self-employed example
Say your net profit is $100,000, single, one exemption, no city tax. SE tax: about $14,130 on the $92,350 base. Half that ($7,065) is deductible. Federal on the rest: about $14,870. Michigan: about $3,999 on $94,100 taxable. Total: roughly $33,000 in tax — an effective rate near 33% of gross profit. The tool computes your exact number with your settings and city.