Is Self-Employment Tax Deductible? The Half You Get Back
The above-the-line deduction for the employer half — where it goes, what it does not reduce, and the QBI interaction
Reviewed by the Fairlight Accounting cross-border tax team — U.S. & Canadian Tax Desks
Half of your self-employment tax is deductible as an adjustment to income on Schedule 1, reducing adjusted gross income whether or not you itemize. The deduction represents the employer's share of payroll tax a business would deduct if it had employees. It reduces income tax, not self-employment tax itself, and it also reduces qualified business income.
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Why is half deductible?
When a business employs someone, the employer's 7.65 percent share of Social Security and Medicare is a deductible business expense; the employee's 7.65 percent is not deductible to the employee. A self-employed person pays both halves as one 15.3 percent tax. To keep the two situations parallel, the law lets the self-employed person deduct the "employer" half. The other half — the employee-equivalent share — is not deductible, just as an employee cannot deduct the payroll tax withheld from a paycheck.
What does the deduction reduce?
| Reduces | Does not reduce |
|---|---|
| Adjusted gross income (and therefore taxable income) | Self-employment tax itself — the base is fixed at 92.35 percent of net profit and is not lowered again by the deduction |
| Income tax | Net profit on Schedule C (it is a personal adjustment, not a business expense) |
| Qualified business income for the 20 percent deduction (the regulations require it) | The Additional Medicare Tax (only the Social Security and regular Medicare halves are deductible) |
| Thresholds keyed to adjusted gross income (IRA deductibility, education credits, the medical-expense floor) | Net earnings for Social Security benefit purposes |
Because it lowers adjusted gross income, the deduction has second-order effects: it can bring a taxpayer under an income-based phase-out, and it lowers the taxable-income figure tested against the QBI threshold — while also reducing the QBI base itself, which is why the QBI computation treats it as attributable to the business.
Where does it go on the return?
Schedule SE computes the tax and, on its own line, the deductible half. That figure is entered on Schedule 1, Part II, as an adjustment to income, and flows to Form 1040. No election is needed and no Form 4562 or Schedule C entry is involved. For a partner, the deduction is based on the self-employment tax computed on the partner's K-1 income, and is taken on the partner's own return.
How does it interact with the QBI deduction?
The regulations under section 199A treat the deductible half of self-employment tax, the self-employed health insurance deduction, and self-employed retirement contributions as attributable to the trade or business, so they reduce qualified business income. A sole proprietor with US$100,000 of Schedule C profit and US$7,065 of deductible self-employment tax has QBI of US$92,935 (before the other two adjustments), not US$100,000 — a common error in home-prepared returns that overstates the QBI deduction by 20 percent of the omitted amounts.
Worked example
A sole proprietor nets US$90,000 on Schedule C. Self-employment tax: US$90,000 × 0.9235 × 15.3% = US$12,717. Deductible half: US$6,358 on Schedule 1. Adjusted gross income falls from US$90,000 to US$83,642 (before other adjustments). At a 22 percent marginal rate, the deduction saves about US$1,400 of income tax. It does not change the US$12,717 of self-employment tax. For QBI purposes, her qualified business income is US$90,000 − US$6,358 = US$83,642 (further reduced by any health insurance and retirement deductions), so her QBI deduction is 20 percent of that figure, not of US$90,000.
Frequently asked questions
Is self-employment tax deductible?
Half of it is — as an above-the-line adjustment to income on Schedule 1, available whether or not you itemize.
Does the deduction reduce self-employment tax itself?
No. Self-employment tax is computed on a fixed base (92.35 percent of net profit) that already reflects the employer-share adjustment. The deduction reduces income tax only.
Does it reduce qualified business income?
Yes. The regulations treat the deductible half of self-employment tax as attributable to the business, so QBI — and the 20 percent deduction — are computed after it.
Where is the deduction claimed?
Schedule SE computes it; it is entered on Schedule 1, Part II, and flows to Form 1040 as an adjustment to income.
Official sources
The IRS states: “You can deduct the employer-equivalent portion of your self-employment tax in figuring your adjusted gross income. This deduction only affects your income tax. It does not affect either your net earnings from self-employment or your self-employment tax.” — Internal Revenue Service, Self-employment tax (Social Security and Medicare taxes), https://www.irs.gov/businesses/small-businesses-self-employed/self-employment-tax-social-security-and-medicare-taxes
Publication 334 states: “You can deduct one-half of your SE tax on line 15 of Schedule 1 (Form 1040).” — Internal Revenue Service, Publication 334, Tax Guide for Small Business, https://www.irs.gov/publications/p334
Next step
Fairlight Accounting is a cross-border accounting and tax practice with a U.S. Tax Desk and a Canadian Tax Desk. Our U.S. Tax Desk handles Schedule SE and Schedule 1 preparation, QBI computation with the required self-employment adjustments, and adjusted-gross-income planning for phase-outs. See pricing or book a call.
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