Self-Employment Tax Explained: Where That 15.3% Actually Goes

At FreelanceAtlas, we help freelancers understand the money mechanics behind the work without the jargon. This guide covers what the 15.3 percent funds, the 92.35 percent step almost everyone misses, what happens above the Social Security wage base, and what the deductible half really does. For the wider filing picture and the payment schedule that comes with it, read Freelancer Taxes Made Simple and Quarterly Estimated Taxes for Freelancers Explained.

This article is general information, not tax advice. Consult a qualified CPA before making decisions about your own situation.

What Self-Employment Tax Is, and Why Employees Never See Half of It

Self-employment tax is the Social Security and Medicare contribution a freelancer pays on business profit. It is the same system that funds an employee’s Social Security and Medicare, collected a different way. Employees do not escape it. They only ever see half of it.

On payroll, the contribution is split in two. The employee pays one half through withholding, visible on the pay stub, and the employer pays the matching half separately, where it never appears on that stub at all. The IRS confirms the structure in Topic 751: Social Security is 6.2 percent from the employee plus 6.2 percent from the employer, which is 12.4 percent, and Medicare is 1.45 percent plus 1.45 percent, which is 2.9 percent.

When you freelance there is no employer to pay the second half, so you pay both. That is how 6.2 plus 6.2 plus 1.45 plus 1.45 becomes the 15.3 percent self-employment tax rate the IRS publishes. Nothing new was invented for freelancers. The cost was always there, and leaving payroll only made it visible and made it yours to fund.

The 12.4 Percent and the 2.9 Percent: What Each Rate Funds

The two halves of the 15.3 percent fund two programs under two different rules, and the difference matters as soon as your income climbs.

• Social Security, 12.4 percent. This funds retirement, disability, and survivor benefits, and it is capped. The IRS applies it only up to an annual earnings limit, and every dollar above that limit is free of the 12.4 percent.
• Medicare, 2.9 percent. This funds hospital insurance and has no cap. IRS Topic 751 states that there is no wage base limit for Medicare tax, so the 2.9 percent reaches every dollar of net earnings.

Treating 15.3 percent as one indivisible number works only below the Social Security cap. Above it the two rates part company: one stops, one continues. Any calculation that keeps applying a flat 15.3 percent to a high income overstates the bill, sometimes by thousands of dollars. The split matters in the other direction too, because Social Security contributions are recorded against your earnings history and feed your eventual benefit.

The $400 Threshold: When Self-Employment Tax Starts

Self-employment tax begins at a very low level of profit. The IRS requires you to file Schedule SE and pay self-employment tax if your “net earnings from self-employment (excluding church employee income) were $400 or more” for the year.

Four hundred dollars is the entire threshold. It is not $10,000, it is not the standard deduction, and it is not the point at which a client must send you a 1099. Those are separate rules answering separate questions.

Two consequences follow. A side project earning a few thousand dollars alongside a full-time job is over the threshold and owes self-employment tax on that profit, even though the payroll job already withholds Social Security and Medicare from the salary. And the absence of a tax form changes nothing, because the $400 test looks at net earnings rather than at how many forms arrived.

Note that the threshold is measured on net earnings, meaning profit after deductible business expenses, not gross revenue. A freelancer with $9,000 of revenue and $8,800 of legitimate costs has $200 of profit and falls below the line.

The 92.35 Percent Step That Confuses Almost Everyone

Self-employment tax is not applied to your Schedule C net profit. It is applied to 92.35 percent of that profit. This single step is where most freelancers doing the arithmetic at home get a different answer from their tax software, and it is built directly into Schedule SE. The result is called your net earnings from self-employment, and it is that figure, not your profit, that the 15.3 percent touches.

Why the Multiplier Exists

The reasoning becomes clear back at the employee comparison. An employer paying an employee also pays the employer half of Social Security and Medicare, and that contribution is a business expense, deducted before the employer’s own profit is measured. A freelancer has no such separation. Your net profit has not been reduced by the employer half, because you have not paid it yet.

Cutting profit to 92.35 percent before applying the rate approximates that missing business deduction and puts you on comparable footing with the employer-and-employee pair. The 7.65 percent stripped out is exactly the employer-side share of the 15.3 percent.

The practical effect is a lower true rate than the headline. Below the Social Security cap, 15.3 percent of 92.35 percent of profit works out to 14.13 percent of profit.

The Full Calculation: A Freelancer With $80,000 of Net Profit

Take a freelance designer, filing single, with no wage job, whose Schedule C shows $80,000 of net profit for the year. That is revenue after every deductible business expense has already come out.

Step One: Reduce Profit to Net Earnings

$80,000 x 0.9235 = $73,880.00

That $73,880.00 is the net earnings from self-employment. It is far above the $400 threshold, so the tax is owed. It is also below the Social Security wage base, so the full 12.4 percent applies to all of it.

Step Two: Apply 15.3 Percent

$73,880.00 x 0.153 = $11,303.64

Split into its two components, so you can see where the money goes:

• Social Security, 12.4 percent. $73,880.00 x 0.124 = $9,161.12
• Medicare, 2.9 percent. $73,880.00 x 0.029 = $2,142.52
• Total. $9,161.12 + $2,142.52 = $11,303.64, matching the combined-rate result.

Measured against the original profit rather than against net earnings, $11,303.64 divided by $80,000 is an effective rate of 14.13 percent.

Step Three: The Deductible Half

Half of the self-employment tax is deductible in figuring adjusted gross income. The IRS describes it as deducting “the employer-equivalent portion of your self-employment tax in figuring your adjusted gross income.”

$11,303.64 / 2 = $5,651.82

That $5,651.82 is an adjustment to income. It reduces the figure flowing toward AGI from $80,000 to $74,348.18, because $80,000 minus $5,651.82 is $74,348.18.

Now read this twice, because it is the most misunderstood point in the subject. The deduction does not reduce the self-employment tax. That stays at $11,303.64. The deduction reduces adjusted gross income, which affects the separate income tax calculation, and what it is worth in cash depends on your marginal income tax rate. As a purely illustrative figure, at a marginal rate of 20 percent it would save $5,651.82 x 0.20 = $1,130.36. Your actual rate comes from the current bracket table.

Step Four: Income Tax Is Still Coming

The $11,303.64 is not the tax bill. It is one of two tax bills on the same $80,000.

Federal income tax is calculated separately and on top, running through its own path: adjusted gross income, then the standard or itemized deduction, then any qualified business income deduction, then the graduated brackets. None of those steps reduce the self-employment tax already computed. The designer owes $11,303.64 plus whatever the bracket calculation produces, plus any state tax. That is why how you hold tax money through the year is a business system rather than an afterthought.

Above the $184,500 Wage Base: The Second Pass

The Social Security wage base limit for 2026 is $184,500, according to IRS Topic 751. In 2025 it was $176,100. Once net earnings pass that line the 12.4 percent stops and only the 2.9 percent continues. Run the same steps on a freelancer with $220,000 of net profit, filing single, with no wage income.

• Net earnings. $220,000 x 0.9235 = $203,170.00
• Social Security, 12.4 percent, capped at $184,500. $184,500 x 0.124 = $22,878.00
• Medicare, 2.9 percent, on the whole $203,170.00. $203,170.00 x 0.029 = $5,891.93
• Total self-employment tax. $22,878.00 + $5,891.93 = $28,769.93

Look at what happened above the cap. Net earnings exceed the wage base by $203,170.00 minus $184,500, which is $18,670.00. That slice carries 2.9 percent, or $541.43, and no Social Security tax at all. Had the 12.4 percent continued, the same slice would have added $18,670.00 x 0.124 = $2,315.08.

The cross-check confirms it. A flat 15.3 percent on the full net earnings would give $203,170.00 x 0.153 = $31,085.01, and the actual $28,769.93 is lower by exactly $2,315.08. This is why a freelancer who crosses the wage base mid-year sees the self-employment cost of the next dollar of profit fall from 15.3 percent to 2.9 percent.

The 0.9 Percent Additional Medicare Tax and Its Frozen Thresholds

A separate 0.9 percent Additional Medicare Tax applies above certain income levels. The IRS sets those thresholds in Topic 560 at $200,000 for single and head of household filers, $250,000 for married filing jointly, and $125,000 for married filing separately, measured on wages and self-employment income above the threshold.

The structural detail that matters is that these thresholds are not indexed for inflation. They have been unchanged since 2013. Every year of income growth pulls more freelancers over a line that never moves.

Apply it to the second example. The single filer with $203,170.00 of net earnings exceeds the $200,000 threshold by $3,170.00, so the Additional Medicare Tax is $3,170.00 x 0.009 = $28.53. Combined, that filer owes $28,769.93 + $28.53 = $28,798.46 before any federal income tax.

Two cautions. The 0.9 percent is figured on its own form and is not part of the Schedule SE self-employment tax, so it sits outside the one-half deduction below. And the joint threshold of $250,000 is measured on the couple’s combined wages and self-employment income, so a freelancer married to a high earner can cross it on the household total alone.

The Deductible Half: What It Does and What It Does Not Do

You may deduct one half of your self-employment tax in figuring adjusted gross income. It is a real and valuable deduction, available whether or not you itemize, because it is an adjustment to income rather than an itemized deduction. What it does not do is reduce the self-employment tax itself.

• The self-employment tax is computed first and is final. In the $80,000 example it is $11,303.64, and nothing later in the return changes that figure.
• Half of it then becomes an adjustment to income. The $5,651.82 reduces adjusted gross income and therefore taxable income for the income tax calculation.
• The cash value depends on your marginal income tax rate, not on the self-employment tax rate, so the same deduction is worth more to a higher-rate taxpayer.
• It is not a credit. A credit reduces tax dollar for dollar. This reduces income, and only then reduces tax by whatever rate applies.

The mirror-image trap is just as common. Because the deduction lowers AGI, some freelancers assume the self-employment tax should be recalculated on the lower figure. It should not. Schedule SE feeds the income tax calculation, never the reverse.

How Schedule SE Flows Into Form 1040

Business income and deductible expenses go on Schedule C, which produces net profit. That profit carries to Schedule SE, where the 92.35 percent multiplier is applied, the wage base cap is enforced, and the tax is calculated. Schedule SE then sends two outputs to different places: the full self-employment tax is added to total tax on Form 1040, and the deductible half moves to Schedule 1 as an adjustment to income.

That structure is the whole answer to why one profit figure produces two taxes. Net profit is used twice, under two different sets of rules, and the self-employment tax is not reduced by the standard deduction, by itemized deductions, or by the qualified business income deduction.

Why This Number Blindsides First-Year Freelancers

The first-year surprise is structural rather than careless. Someone leaving a payroll job carries an intuition built entirely from a pay stub, and the pay stub was never showing the employer half.

• Withholding disappeared, but the obligation did not. On payroll, Social Security and Medicare left the paycheck before it landed. Freelance income arrives whole, which makes the gross number feel spendable.
• Only income tax gets budgeted. A freelancer who reads about brackets and sets aside a percentage based on them has planned for one tax. The 14.13 percent effective self-employment cost sits entirely outside that plan.
• The deadline structure changed. Payroll settles the liability every pay period. Freelance income does not, which creates the quarterly estimated payment obligation and the risk of underpayment penalties on top of the tax.

The fix is a pricing question as much as a tax question. Work out self-employment tax plus expected income tax as a percentage of profit, move that percentage aside as each client payment arrives, and check that your rates were set with the cost included, which is the arithmetic behind what you actually need to charge to hit a target income.

The S-Corp Election and the Reasonable Compensation Standard

At higher and stable income levels, some freelancers ask an accountant about electing S corporation tax treatment, because it changes how much of your income self-employment tax reaches.

Under S corporation treatment the owner is an employee of the business and is paid a salary. Payroll taxes apply to that salary. Remaining profit can be taken as a distribution, and distributions are not subject to self-employment tax. The size of any saving depends on how the income divides.

That division is governed by a standard, not a formula. The IRS guidance on S corporation officers states that “distributions and other payments by an S corporation to a corporate officer must be treated as wages to the extent the amounts are reasonable compensation for services.” The operative words are “reasonable compensation.”

Reasonable compensation is a facts-and-circumstances test. It turns on your duties, your hours, your experience, what comparable roles pay in your market, and what the business actually does. There is no percentage rule of thumb, and this article will not print one, because any fixed split circulating online was invented outside the IRS and is not a defense in an examination.

Treat the election as a later-stage decision a CPA prices against your real numbers, weighing payroll administration, extra filings, and your state’s treatment of S corporations. It is an entity-level question, so it belongs alongside the structural choices in Sole Proprietor vs LLC for Freelancers.

Conclusion

The decision in front of you is not whether to pay self-employment tax. It is whether your pricing and your cash system already account for it. Run your own numbers in the order used here: take net profit, multiply by 0.9235, apply 12.4 percent up to $184,500 of net earnings and 2.9 percent on all of it, and treat the result as a figure income tax gets added to. On $80,000 of profit that figure was $11,303.64, and no later deduction changed it.

Then act on the two things in your control. Move a fixed percentage of every client payment into a separate account the day it arrives, so the quarterly obligation is funded before it falls due. And when you next set or raise a rate, price with this cost visible, because the freelancer absorbing the employer half needs a higher headline number than a salaried peer does. If your profit is high and stable, that is the point to take the S corporation question to a CPA with real figures.

Key Takeaways

• Self-employment tax is 15.3 percent, made up of 12.4 percent for Social Security and 2.9 percent for Medicare, and the IRS charges it in addition to federal income tax on the same profit.
• The tax applies to 92.35 percent of Schedule C net profit rather than the full amount, so $80,000 of profit gives $73,880.00 of net earnings and a self-employment tax of $11,303.64, an effective 14.13 percent of profit.
• The tax is owed once net earnings from self-employment reach $400, a threshold far below the amount that triggers a client information return, and it applies whether or not any tax form arrives.
• The 12.4 percent Social Security component stops at the 2026 wage base of $184,500 in net earnings per IRS Topic 751, while the 2.9 percent Medicare component has no cap at all.
• The 0.9 percent Additional Medicare Tax applies above $200,000 for single filers, $250,000 for joint filers, and $125,000 for married filing separately, and those thresholds are not indexed for inflation.
• Half of your self-employment tax is deductible in figuring adjusted gross income, but that deduction lowers AGI for the income tax calculation only and never lowers the self-employment tax itself.

Frequently Asked Questions

How do I calculate self-employment tax on my freelance income?

Start with net profit from Schedule C, which is revenue minus deductible business expenses. Multiply that profit by 0.9235 to get net earnings from self-employment. Apply 12.4 percent for Social Security to those net earnings up to the annual wage base, which IRS Topic 751 sets at $184,500 for 2026, and apply 2.9 percent for Medicare to all of the net earnings with no cap. On $80,000 of net profit that gives net earnings of $73,880.00 and a self-employment tax of $11,303.64, the figure Schedule SE computes.

Why is self-employment tax calculated on 92.35 percent of profit instead of all of it?

The multiplier puts self-employed people on comparable footing with the employer-and-employee arrangement. An employer deducts the employer half of Social Security and Medicare as a business expense before measuring profit, so the employee is never taxed on that amount. A freelancer has no employer to make that payment, so net profit has not been reduced by it. Cutting profit to 92.35 percent before applying the rate approximates the missing deduction, and the 7.65 percent removed is precisely the employer-side share of the 15.3 percent.

Do I pay self-employment tax and income tax on the same money?

Yes. The two taxes are calculated separately under different rules and both apply to the same net profit. Schedule SE produces the self-employment tax, which is added directly to total tax on Form 1040. Federal income tax runs through its own path of adjusted gross income, deductions, and the bracket table. The standard deduction, itemized deductions, and the qualified business income deduction reduce taxable income only, and none of them touch the self-employment tax figure. Budgeting for only one of the two is the most common first-year cash flow mistake.

What happens to my self-employment tax above the Social Security wage base?

The 12.4 percent Social Security portion stops at the wage base and the 2.9 percent Medicare portion continues without limit. For 2026 the wage base is $184,500 according to IRS Topic 751. A freelancer with $220,000 of net profit has net earnings of $203,170.00, pays $22,878.00 of Social Security tax on the capped $184,500, and pays $5,891.93 of Medicare tax on the full $203,170.00, for a total of $28,769.93. The $18,670.00 of net earnings above the cap carries only $541.43 of Medicare tax instead of the $2,315.08 of Social Security tax it would otherwise carry.

Does deducting half my self-employment tax lower the self-employment tax I owe?

No, and this is the most misunderstood point in the whole calculation. The IRS lets you deduct the employer-equivalent portion of your self-employment tax in figuring adjusted gross income, so half of it becomes an adjustment to income on Schedule 1. That reduces AGI and therefore taxable income for the federal income tax calculation. It leaves the self-employment tax itself unchanged. On $80,000 of net profit the self-employment tax stays at $11,303.64 while $5,651.82 comes off AGI. The cash value of that deduction depends on your marginal income tax rate.