Self Employment Tax

Self-Employment Tax: The 15.3% Surprise

Most people who leave W-2 employment to freelance or start a business know they'll owe income tax on their earnings. Fewer understand that they'll also owe a separate layer of tax on those same earnings before income tax is even calculated—a tax that is larger than most people expect and that catches a significant number of first-year self-employed workers completely off guard when April arrives.

Self-employment tax is the self-employed worker's version of FICA—the Social Security and Medicare taxes that employees and employers split. As a W-2 employee, you pay 7.65% in FICA taxes, and your employer matches another 7.65%, for a total of 15.3%. You see 7.65% on your pay stub; the employer's matching contribution is invisible to you.

As a self-employed worker, you pay both halves. All of it. The 15.3% is entirely yours.

THE MECHANICS

Self-employment tax applies to net self-employment income—gross revenue from the business minus deductible business expenses. It consists of two components:

Social Security tax: 12.4% on net self-employment income up to the wage base. The Social Security wage base for 2024 is $168,600. Income above this threshold is not subject to the 12.4% Social Security portion.

Medicare tax: 2.9% on all net self-employment income with no cap. For higher earners, an additional 0.9% Medicare surtax applies to earned income above $200,000 (single filers) or $250,000 (married filing jointly), bringing the Medicare portion to 3.8% above those thresholds.

Combined rate below the wage base: 15.3%

Combined rate above the wage base: 2.9% (plus 0.9% surtax for high earners)

The tax is calculated on 92.35% of net self-employment income, not 100%. This adjustment—equivalent to the employee's share of FICA—partially offsets the employer portion, reflecting that employers cannot deduct the matching FICA they pay on behalf of employees from the employee's gross income. Self-employed workers receive an equivalent adjustment.

Actual calculation: Net self-employment income × 92.35% × 15.3% = Self-employment tax

On $75,000 in net self-employment income:

$75,000 × 0.9235 = $69,263 $69,263 × 0.153 = $10,597 in self-employment tax

That $10,597 is owed in addition to income tax. A freelancer in the 22% bracket with $75,000 in net SE income owes approximately $10,597 in SE tax plus approximately $10,000 to $12,000 in income tax (after standard deduction)—a combined federal tax liability of $20,000 to $23,000 on $75,000 in income. The effective total federal rate is 27% to 31%.

Someone who set aside only 22% for income tax is short by approximately $10,000.

THE DEDUCTIONS THAT REDUCE THE PAIN

Two deductions partially offset the SE tax burden:

Deduction for half of SE tax (above-the-line): Self-employed workers can deduct half of the self-employment tax paid from their gross income when calculating adjusted gross income. In the example above, half of $10,597 is $5,299. This deduction reduces taxable income—it doesn't reduce the SE tax itself, but it reduces the income tax calculated on that income.

At 22% marginal rate, the $5,299 deduction saves approximately $1,166 in income tax. This brings the effective combined rate down somewhat—but the SE tax liability itself is unchanged.

Qualified Business Income (QBI) Deduction (Section 199A): The 2017 Tax Cuts and Jobs Act introduced a deduction of up to 20% of qualified business income for pass-through entities, including sole proprietorships. For self-employed workers below the income threshold ($182,100 for single filers, $364,200 for married filing jointly in 2024), the deduction is straightforward: 20% of net SE income is deductible from taxable income.

On $75,000 in net SE income, the QBI deduction is $15,000. At 22%, this saves approximately $3,300 in income tax—a meaningful reduction in the total tax burden, though again, it doesn't reduce the SE tax itself.

Combined, these two deductions—the SE tax deduction and the QBI deduction—meaningfully reduce the income tax portion of the total liability. They do not change the self-employment tax.

THE BRACKET IMPACT ON TOTAL TAX RATES

Because SE tax and income tax stack, the marginal rate on self-employment income is higher than the income tax bracket alone suggests. For a taxpayer in the 22% income tax bracket, the marginal rate on the next dollar of SE income is:

SE tax on the dollar (at 92.35% × 15.3%): 14.13%

Income tax on the dollar minus the SE deduction (22% × (1 - 7.65%)): 20.32% Less the QBI deduction (22% × 20%): -4.40%

Net combined marginal rate: approximately 30%

This calculation is simplified, but the directional result is consistent: self-employment income is taxed at a higher combined rate than equivalent W-2 income at the same nominal bracket—typically 5 to 8 percentage points higher than the bracket rate alone suggests.

This has planning implications for pricing: a self-employed consultant who needs $100,000 in after-tax income needs to price for a significantly higher gross revenue than a W-2 employee who nets the same take-home pay. The self-employment tax load is a cost of goods, effectively, that must be built into pricing to achieve equivalent after-tax outcomes.

THE SAVINGS RATE ADJUSTMENT

The standard personal finance advice to "save 20% of income" assumes W-2 employment where FICA is already withheld. Self-employed workers must first set aside their SE tax and income tax before calculating the savings rate on what remains.

A practical allocation system for a freelancer:

Set aside 30% to 35% of each gross payment received into a dedicated tax savings account. This fund covers both SE tax and income tax. The exact percentage depends on your bracket, state income taxes, and deductions—but 30% is a reasonable floor for a single filer earning $60,000 to $100,000 in net SE income. Run the actual calculation once with your accountant to calibrate the right percentage for your situation, then apply it consistently.

Pay estimated taxes quarterly from this fund, as discussed in Article 1. What remains after estimated payments at year-end is your actual tax refund or final balance due—a calibration check on whether your set-aside rate was accurate.

The rest—gross payments minus the tax set-aside—is available for business expenses, personal expenses, retirement contributions, and savings. Retirement contributions from the SE income (SEP IRA, Solo 401(k)) both provide a deduction and reduce taxable SE income for the QBI deduction calculation, creating a compounding tax benefit.

THE WAGE-AND-PROFIT SPLIT FOR S CORPORATIONS

Business owners operating as S corporations have an additional tool: the ability to split income between salary (subject to SE tax) and distributions (not subject to SE tax). An S corporation owner who earns $180,000 in net business income can pay themselves a "reasonable salary" of $90,000 (subject to FICA/SE tax) and take the remaining $90,000 as a distribution—which is not subject to SE tax, only income tax.

The SE tax savings on $90,000 in distributions: approximately $12,735 (14.13% effective SE rate). The cost is the additional administrative burden and expense of maintaining payroll for an S corporation (payroll processing, employer FICA matches on the salary portion, quarterly payroll filings, additional state requirements). Professional estimates typically suggest an S corporation election becomes cost-beneficial at around $50,000 to $80,000 in net self-employment income, depending on state, the complexity of the business, and the cost of professional services.

The S corporation option is not relevant for workers early in self-employment—it requires the business to be structured as a corporation or LLC electing S status, a payroll system, and the discipline to pay a reasonable salary that the IRS would not characterize as artificially low to avoid SE tax. It is, however, a legitimate and widely used strategy for established self-employed workers with consistent high income.

Self-employment tax is not a surprise if you know it's coming. For every $100 in net self-employment income, expect to owe approximately $14 to $15 in SE tax before income tax is calculated. Build that into your pricing, your savings rate, and your estimated payment calculations—and none of it will be a surprise when the return is filed.