How Self-Employment Tax Actually Works

Q: Why is SE tax higher than what an employee pays in FICA?

It isn't actually higher in total — as a self-employed person you're paying both the 'employee' and 'employer' halves of FICA that would normally be split with an employer. The 92.35% adjustment partially accounts for this.

Q: Does SE tax replace income tax?

No. SE tax is separate from and in addition to federal (and state) income tax. You owe both on your self-employment earnings.

Q: What income counts toward SE tax?

Net earnings from self-employment — your business income minus your ordinary and necessary business expenses — is what's subject to SE tax, not your gross revenue.

Q: Is there a minimum income before I owe SE tax?

Yes, generally you don't owe SE tax if your net self-employment earnings are below $400 for the year.

Q: Can I reduce my SE tax by forming an S-Corp?

Some business owners use an S-Corp structure to pay themselves a reasonable salary (subject to FICA) plus additional distributions (not subject to SE tax), potentially reducing total SE/FICA tax — but this involves added complexity and compliance requirements. Consult a CPA before restructuring.

If you've ever looked at your first 1099 and wondered why the tax bill felt so much bigger than a W-2 job, self-employment tax is the reason. Here's the plain-English version of how it's actually calculated.

The Core Idea: You're Paying Both Halves

When you're an employee, FICA tax (Social Security and Medicare) is split 50/50 between you and your employer — each pays 7.65%. When you're self-employed, there's no employer to split it with, so you pay the full 15.3% yourself. That's the entire reason self-employment tax exists.

Step 1: The 92.35% Adjustment

Before applying the 15.3% rate, your net self-employment income is multiplied by 92.35%. This exists because employees' effective FICA base is reduced by the value of the employer's matching contribution (which isn't itself taxed as employee income) — the 92.35% figure roughly approximates that same relief for self-employed taxpayers.

Step 2: Social Security Portion (12.4%)

The 12.4% Social Security portion applies to your adjusted SE income up to an annual wage base cap. Earnings above that cap — from all sources combined, including any W-2 wages — aren't subject to the Social Security portion.

Step 3: Medicare Portion (2.9%)

Unlike Social Security, the 2.9% Medicare portion has no cap. It applies to all of your adjusted SE income, no matter how high your total earnings are. High earners may also owe an Additional Medicare Tax of 0.9% above certain thresholds.

The Silver Lining: Half Is Deductible

You get to deduct half of your total SE tax as an adjustment to income on your federal return — this doesn't reduce your SE tax bill directly, but it does lower your taxable income for regular income tax purposes.

See your own SE tax breakdown:

Use the Free SE Tax Calculator →

Frequently Asked Questions

Why is SE tax higher than what an employee pays in FICA?

It isn't actually higher in total — you're paying both the employee and employer halves that would normally be split. The 92.35% adjustment partially accounts for this.

Does SE tax replace income tax?

No. SE tax is separate from and in addition to income tax.

What income counts toward SE tax?

Net earnings — business income minus ordinary and necessary expenses — not gross revenue.

Is there a minimum income before I owe SE tax?

Generally you don't owe SE tax if net earnings are below $400 for the year.

Can I reduce my SE tax by forming an S-Corp?

Some owners use an S-Corp to split pay into salary and distributions, potentially reducing total SE/FICA tax — but this adds complexity. Consult a CPA first.