Self-Employment Tax and Adjustments
Self-employment tax generally starts with 92.35% of net self-employment profit, not gross receipts. Apply the Social Security wage-base and Medicare rules, then calculate the deductible part separately from the tax itself.
Keep the three amounts separate
| Amount | How it is used | Do not confuse it with |
|---|---|---|
| Business net profit | Receipts less allowable business costs | Gross sales or cash in the bank |
| Net earnings for SE tax | Generally net profit × 92.35% | Taxable income after the standard deduction |
| SE tax | Social Security and Medicare components | Ordinary income tax |
| Deductible part of SE tax | Adjustment in arriving at AGI | A credit that cancels the SE tax |
Business net profit
- How it is used
- Receipts less allowable business costs
- Do not confuse it with
- Gross sales or cash in the bank
Net earnings for SE tax
- How it is used
- Generally net profit × 92.35%
- Do not confuse it with
- Taxable income after the standard deduction
SE tax
- How it is used
- Social Security and Medicare components
- Do not confuse it with
- Ordinary income tax
Deductible part of SE tax
- How it is used
- Adjustment in arriving at AGI
- Do not confuse it with
- A credit that cancels the SE tax
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For the July 2026-February 2027 SEE window: tax law through December 31, 2025; questions generally use calendar year 2025.
How to work through the decision
- 1Find net profit
- 2Calculate net earnings and tax
- 3Compute the income adjustment
Start with net earnings rather than gross receipts
For the ordinary Schedule SE computation, start with the applicable net self-employment profit after business deductions, not gross customer payments. Multiply that profit by 92.35% to determine the regular net-earnings base. This factor does not turn every business receipt into eligible earnings: special categories, losses, optional methods and exclusions require their own treatment. Net earnings of $400 or more generally trigger the ordinary SE-tax filing requirement.
The basic tax has two components: 12.4% Social Security and 2.9% Medicare. The 15.3% combined shortcut works only when the entire earnings base is subject to both components and no other adjustments apply. Social Security has an annual combined wage and SE-earnings limit, while the regular Medicare component does not have that cap. Write the components separately whenever the taxpayer also has wages or large earnings.
Use wages first when measuring the Social Security cap
For 2025 the Social Security earnings ceiling is $176,100. Subtract the applicable Social Security wages and tips already counted against that ceiling to find the space remaining for self-employment earnings. Apply 12.4% only to the smaller of that remaining space and the SE earnings base. Apply 2.9% to the full ordinary SE earnings base. If covered wages already reach the ceiling, the ordinary SE Social Security component is zero, but Medicare can still apply.
Additional Medicare Tax is a separate 0.9% calculation above the applicable combined-income threshold, with different filing-status rules and coordination with wages. It is not part of the ordinary 15.3% shortcut or the Schedule SE half-tax deduction. Where the problem states that Additional Medicare Tax is absent, keep that assumption visible instead of treating the shortcut as a universal rule.
| Component | Ordinary base | 2025 treatment |
|---|---|---|
| Social Security | SE earnings limited by remaining wage-base capacity | 12.4%; combined ceiling $176,100 |
| Medicare | Ordinary SE earnings base | 2.9%; no Social Security-style cap |
| Deductible part | One-half of ordinary Schedule SE tax | Adjustment in the income-tax calculation |
Social Security
- Ordinary base
- SE earnings limited by remaining wage-base capacity
- 2025 treatment
- 12.4%; combined ceiling $176,100
Medicare
- Ordinary base
- Ordinary SE earnings base
- 2025 treatment
- 2.9%; no Social Security-style cap
Deductible part
- Ordinary base
- One-half of ordinary Schedule SE tax
- 2025 treatment
- Adjustment in the income-tax calculation
Take the adjustment without reducing the business profit twice
The deductible part is generally one-half of the ordinary Schedule SE tax. It is an income-tax adjustment, not a refund of half the SE tax and not another Schedule C business expense. Keep the net-profit figure, net-earnings base, SE tax and income adjustment on separate lines. If you deduct the adjustment from profit before recomputing SE tax, you create a circular and incorrect calculation.
Other self-employed adjustments, such as qualifying health-insurance or retirement contributions, have their own conditions and limits. They should not simply be subtracted from the SE earnings base because they reduce income tax. For exam purposes, first solve the supplied Schedule SE facts, then place the allowed adjustment in the individual-return sequence. Round at the requested stage; early rounding can cause an otherwise correct computation to miss the answer choices.
Original worked example
A basic Schedule SE calculation
Net profit is $40,000. Assume no wages, no other SE income, earnings below the Social Security cap and no Additional Medicare Tax.
- 1
Net earnings = $40,000 × 92.35% = $36,940.
- 2
SE tax = $36,940 × 15.3% = $5,651.82 before return rounding.
- 3
Deductible part = $5,651.82 ÷ 2 = $2,825.91 before rounding.
Result
About $5,652 SE tax and a separate $2,826 AGI adjustment.
The adjustment does not reduce Schedule C profit or erase half the tax bill.
Apply the method to different facts
Original worked case 2
Wages use part of the Social Security ceiling
For 2025 a taxpayer has $150,000 Social Security wages and $40,000 net self-employment profit. Assume the ordinary method, no other SE items and no Additional Medicare Tax.
- SE earnings: $40,000 × 92.35% = $36,940. Remaining Social Security capacity: $176,100 - $150,000 = $26,100.
- Social Security component: $26,100 × 12.4% = $3,236.40. Medicare component: $36,940 × 2.9% = $1,071.26.
- Total ordinary SE tax is $4,307.66. One-half is $2,153.83 before return rounding.
About $4,308 SE tax and $2,154 adjustment. Applying 15.3% to all $36,940 would overstate the Social Security component.
Mistakes to catch
- Applying 15.3% directly to gross receipts.
- Ignoring wages already counted toward the Social Security wage base.
Check your understanding
Does the standard deduction reduce net earnings for SE tax?
No. The standard deduction is part of the income-tax calculation. Schedule SE generally starts from net self-employment profit and its own adjustments.
2. With no wages and $20,000 ordinary net profit, what is the regular net-earnings base?
Answer: $18,470.
Apply 92.35% to net profit. Gross receipts are not the starting point if the business has deductible expenses.
3. Does the deductible half of SE tax reduce Schedule C profit?
Answer: No. It is a separate income-tax adjustment.
The taxpayer still owes the full computed SE tax. Treating half as a business expense would incorrectly reduce the base used to calculate that tax.
Put the rule into practice
Create an account for EA practice, then work on the decisions you missed.
Sources and scope
Source check: . IRS and PSI materials support the factual rules. Worked cases and suggested study sequences are original educational examples, not official exam questions or IRS study requirements.
- PSI SEE Candidate Information Bulletin
Exam format, scored domain allocations, tested tax year and exam procedures; see Study Materials and Examination Content Outlines.
- IRS Schedule SE (2025)
Net earnings factor, Social Security/Medicare calculation and deductible part of SE tax.
- IRS Publication 17 (2025)
Individual income, deductions, tax and credit framework; use the chapter relevant to the rule.
Use the version applicable to your testing window. Live IRS pages can advance to a later tax year. These notes are exam study material; examples state simplifying assumptions.