How is self-employment tax calculated?

Federal SE tax applies to 92.35% of net self-employment earnings at 15.3% — 12.4% Social Security up to the annual wage base (176,100 dollars for 2025) plus 2.9% Medicare on all net earnings. This covers both the employer and employee halves of FICA.

What is the deductible half of SE tax?

You may deduct one-half of your self-employment tax when computing income tax. The calculator subtracts this half before applying Maine's income tax brackets, since Maine starts from federal adjusted gross income.

Does Maine tax self-employment income?

Yes. Maine taxes net self-employment income through its regular graduated income tax (5.8%, 6.75%, 7.15%) after the standard deduction, personal exemption, and the half-SE-tax adjustment. There is no separate Maine self-employment tax.

Do I also owe federal income tax?

Yes — this calculator shows federal SE tax and Maine state tax. Federal income tax on your business profit is separate and depends on your full return, so consult a federal calculator or tax professional for that portion.

When do I pay self-employment tax?

Self-employed people generally pay through quarterly estimated tax payments to the IRS and Maine Revenue Services, since no employer withholds for them. Underpaying during the year can trigger penalties.

Maine Self-Employment Tax Calculator

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If you freelance or run a business in Maine, you owe self-employment tax to cover Social Security and Medicare — both halves, since you are employer and employee — plus Maine state income tax on your profit. This calculator computes the federal 15.3% SE tax correctly (on 92.35% of net earnings, with the Social Security portion capped at the wage base), applies the deductible half, and then layers Maine’s graduated income tax on top.

How it works

Self-employment tax follows the IRS Schedule SE method, and Maine income tax sits on the net-of-adjustment figure:

Net earnings subject to SE tax. Multiply net self-employment income by 92.35% (this excludes the employer-equivalent portion).
Federal SE tax. Apply 12.4% Social Security up to the annual wage base ($176,100 for 2025) and 2.9% Medicare on all of it — a combined 15.3% below the cap.
Deduct half. Subtract one-half of the SE tax from income before computing income tax.
Maine income tax. Subtract the Maine standard deduction and $5,000 personal exemption, then apply the 5.8% / 6.75% / 7.15% brackets.

Tips and example

On $80,000 of net self-employment income, 92.35% is $73,880. The full 15.3% applies (below the SS cap), giving SE tax of about $11,304. Half of that, ~$5,652, is deducted before Maine income tax. After the Maine standard deduction and exemption, the remaining taxable income is taxed at Maine’s graduated rates, adding a few thousand more.

Because no employer withholds for you, set aside money each quarter for both federal and Maine estimated payments. This tool covers SE tax and Maine state tax; your federal income tax is a separate line that depends on your full return.