How is self-employment tax calculated?

Self-employment tax is 15.3% (12.4% Social Security + 2.9% Medicare) applied to 92.35% of your net self-employment earnings. The Social Security portion stops at the annual wage base ($168,600 in 2024); Medicare has no cap.

Can I deduct part of my SE tax?

Yes. You deduct one-half of your self-employment tax as an above-the-line adjustment to income. This lowers your federal and Wisconsin taxable income, partially offsetting the SE tax burden. This tool applies that deduction before figuring Wisconsin tax.

Does Wisconsin have its own self-employment tax?

No. Wisconsin does not levy a separate self-employment tax. Self-employed Wisconsin residents pay the federal SE tax plus regular Wisconsin income tax (3.50% to 7.65%) on their net profit, which this calculator combines.

Do I need to make quarterly estimated payments?

Generally yes. If you expect to owe $1,000 or more in federal tax, you must make quarterly estimated payments to the IRS, and Wisconsin requires estimated payments if you expect to owe $500 or more. This tool splits your total into four quarters.

Is the 92.35% factor important?

Yes. SE tax is applied to 92.35% of net earnings, not 100%, because that factor approximates the employer-share deduction a W-2 employee gets. Skipping it overstates your SE tax by about 7.65%.

Wisconsin Self-Employment Tax Calculator

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Self-employed Wisconsin residents owe federal self-employment tax plus regular Wisconsin income tax on their net profit. This calculator combines both, applies the deductible half of SE tax, and splits the result into quarterly estimated payments.

How it works

Self-employment tax is figured on 92.35 percent of your net earnings:

SE base   = net profit × 0.9235
SE tax    = 12.4% (up to $168,600 base) + 2.9% Medicare (no cap)
half SE   = SE tax ÷ 2  (deductible adjustment)

For Wisconsin income tax, your taxable income is net profit minus the half-SE deduction and the standard deduction, taxed by the 2024 brackets (3.50 percent to 7.65 percent). Wisconsin does not add its own SE tax. The total tax is the SE tax plus the Wisconsin income tax, divided by four for quarterly estimates.

Example

On 80,000 dollars of net profit, the SE base is 73,880 dollars. The SE tax is 12.4 percent + 2.9 percent of that = 15.3 percent ≈ 11,304 dollars, half of which (5,652 dollars) is deductible. Wisconsin income tax on the reduced base is roughly 3,000 dollars. Total tax near 14,300 dollars, or about 3,575 dollars per quarter.

Notes

This is an estimate, not tax advice. It does not include federal income tax (only the SE component and Wisconsin state tax), the qualified business income deduction, additional Medicare tax on high earners, or self-employed health and retirement deductions. For a full picture combine this with federal income tax. Confirm Wisconsin specifics at revenue.wi.gov and federal rules at irs.gov.