self-employment tax: the 15.3% deep dive

What is self-employment tax?

Self-employment tax (SE tax) is the 1099 equivalent of the FICA payroll tax W-2 employees pay. It's split between Social Security and Medicare:

• Social Security: 12.4% of your net earnings (capped at a maximum taxable income of $168,600 in 2024)
• Medicare: 2.9% of all net earnings (no cap)
• Additional Medicare: 0.9% on high earners (over $200k single, $250k married)

Total: 15.3% for most people, plus 0.9% if you're high-earning. This is on top of federal and state income tax.

The 15.3% breakdown

Let's say you have $50,000 in net business profit (Schedule C). Here's how SE tax is calculated:

Net profit ($50,000) × 92.35% (because you get to deduct half your SE tax) = $46,175 × 15.3% = $7,065 self-employment tax.

Breaking it down:

• Social Security: $46,175 × 12.4% = $5,726
• Medicare: $46,175 × 2.9% = $1,338
• Total: $7,065

You then deduct half of this ($3,532) on your Form 1040 line 15 as an "above-the-line" deduction, reducing your taxable income.

Why it feels unfair (and how W-2 hides it)

When you're a W-2 employee, your paycheck shows:

• 6.2% Social Security tax (employee portion)
• 1.45% Medicare tax (employee portion)
• Total "visible": 7.65%

But your employer also pays a matching 7.65%. So the total is still 15.3%, but the employer portion is hidden from you. You never see it on your paycheck.

As a 1099 creator, you are the employer and the employee. You pay both halves. This is why it feels like you're paying more—you are seeing the full 15.3%.

How to calculate it

You use Schedule SE (Self-Employment Tax) form, which has two sections: Short Form and Long Form. Most 1099 creators use Short Form.

Schedule SE, Short Form

1. Start with net profit from Schedule C, line 31 (the line that shows your business net profit)
2. Multiply by 92.35% (this is the "deductible portion" of SE tax)
3. This is your "net earnings from self-employment"
4. Multiply by 15.3% = your SE tax

Schedule SE, Long Form

You use this if you have multiple businesses, receive wages as an employee (which reduces the amount subject to SE tax), or have complex income sources. It's the same math but with more lines for detail.

The SE tax deduction

Here's the benefit: on Form 1040 line 15, you deduct half your SE tax above the line, meaning it reduces your adjusted gross income (AGI).

Continuing the example: If your SE tax is $7,065, you deduct $3,532.50 on line 15. Your taxable income is lowered by $3,532.50, which reduces your federal income tax by roughly 24% (if you're in the 24% bracket) = $848 in tax savings.

So while you pay $7,065 in SE tax, the deduction saves you ~$848 in income tax, netting $6,217 in total SE tax cost.

Income thresholds and caps

Social Security cap

In 2024, the first $168,600 of net earnings is subject to the 12.4% Social Security tax. Anything above that is not subject to SS tax (though it's still subject to Medicare).

Example: If you earn $200,000, SE tax is:

• $168,600 × 12.4% = $20,900 (Social Security)
• $200,000 × 2.9% = $5,800 (Medicare)
• Total: $26,700 (not $30,600)

The cap changes annually based on wage inflation.

Additional Medicare tax

If your total Medicare wages exceed $200,000 (single) or $250,000 (married), you owe an additional 0.9% Medicare tax on the excess. This is both for wages and SE earnings combined.

Minimum income for filing

If you have self-employment income of $400 or more, you must file Schedule SE and Form 1040 (even if your total income is below the standard deduction). Below $400, you can skip SE tax and just pay regular income tax.

The S-corp workaround

Here's where an S-corp can save you money. Instead of being taxed as a sole proprietor or LLC (pass-through), you elect to be taxed as an S-corp. You then:

1. Pay yourself a "reasonable salary" via W-2 (subject to SE tax)
2. Take distributions of remaining profit (not subject to SE tax)

Key: Only the W-2 salary portion is subject to SE tax. The distributions are not.

Real example: $80,000 net profit

Sole proprietor (current situation):

• Net profit: $80,000
• SE tax: $80,000 × 92.35% × 15.3% = $11,293
• Deduction (half SE tax): -$5,647
• Net cost: $6,417 (plus you owe income tax on the full $80k)

S-corp election:

• Salary: $60,000 (typical "reasonable salary" for this income)
• Distributions: $20,000
• SE tax on salary: $60,000 × 92.35% × 15.3% = $8,470
• Deduction (half SE tax): -$4,235
• Net cost: $4,785
• Savings: $6,417 – $4,785 = $1,632

But the trade-off: you now run payroll (quarterly filings, W-2 processing), file a separate corporate tax return (Form 1120-S), and face higher CPA fees (~$500–$1,000/year extra).

Real examples at different income levels

$40,000 net profit

SE tax: $40,000 × 92.35% × 15.3% = $5,646

Is an S-corp worth it? No. Your savings would be ~$600 (on a 50/50 split), but you'd pay $500+ in extra accounting. Not worth the complexity.

$80,000 net profit

SE tax: $80,000 × 92.35% × 15.3% = $11,293

S-corp savings: ~$1,600 (with reasonable salary of $60k). Worth considering if you're organized and paying a CPA anyway.

$150,000 net profit

Sole proprietor SE tax: $150,000 × 92.35% × 15.3% = $21,176

S-corp option: Salary $100k, distributions $50k. SE tax = $100k × 92.35% × 15.3% = $14,117. Savings: $7,059.

At this income, an S-corp is likely worth it. The savings exceed the accounting cost.

Bottom line

Self-employment tax is the price of being your own business. The 15.3% feels high because you're paying both the employee and employer portions. You get a partial offset via the SE tax deduction on Form 1040.

For most creators under $100k in profit, just bite the bullet. For those earning $100k+, explore an S-corp election with a CPA. It requires more admin but can save thousands annually.