Self-Employment Tax Explained: What Arizona Freelancers and Business Owners Actually Owe

If you work for yourself, self-employment tax is one of the first things you need to understand — and one of the most misunderstood. Self-employment tax is the 15.3% tax that covers your Social Security and Medicare contributions when you don't have an employer splitting that cost with you.

That's the short version. Here's what it actually means for your business, and how to plan for it instead of being surprised by it.

Why Self-Employed People Pay More

When you're an employee, Social Security and Medicare taxes are split between you and your employer. You each pay 7.65% — 6.2% toward Social Security and 1.45% toward Medicare — for a combined 15.3%.

When you're self-employed, there's no employer to split that with. You're both sides of the equation, which means you're responsible for the full 15.3% yourself. That breaks down into:

• 12.4% for Social Security

• 2.9% for Medicare

This applies whether you're a freelancer, a contractor, or running your own small business. If you're earning self-employment income, this tax is part of your picture.

What Income This Actually Applies To

This is where a lot of people lose clarity: self-employment tax is calculated on your net self-employment income, not your total revenue.

Net income is what's left after your business expenses — not the full amount your business brings in. So if your business grossed $70,000 but you had $20,000 in legitimate expenses, your self-employment tax is based on the $50,000 that's left, not the $70,000.

There's also a small built-in adjustment worth knowing about: only about 92.35% of your net earnings are actually subject to this tax, which accounts for the portion an employer would normally cover on their own side. So for $50,000 in net self-employment income, the taxable portion works out to roughly $46,175 — putting the self-employment tax at approximately $7,065.

This is one of the reasons I recommend tracking expenses monthly rather than reconstructing them once a year. The clearer your numbers are, the more accurately you can plan for what you'll actually owe.

How This Tax Gets Paid

For most self-employed business owners, self-employment tax isn't withheld the way it would be from a paycheck. Instead, it's typically paid through quarterly estimated tax payments, alongside your federal income tax.

This matters because it changes how you need to think about cash flow throughout the year. If you're used to a W-2 job where taxes are handled automatically, this is a real shift — you're now responsible for setting money aside and paying it in on a schedule, rather than having it disappear from each paycheck before you see it.

What I recommend first is setting aside a percentage of your income for taxes as it comes in, rather than waiting until a quarterly deadline to figure out what you owe. It's much easier to keep up with smaller, regular amounts than to scramble for a lump sum four times a year.

A Deduction Worth Knowing About

You can deduct half of your self-employment tax when calculating your income tax. This doesn't reduce the self-employment tax itself, but it does lower your taxable income — which is worth factoring in when you're estimating what you'll owe overall.

Ways to Plan for Self-Employment Tax

None of this needs to feel overwhelming. A few habits make the biggest difference:

• Keep clean, current records. This is the foundation everything else depends on.

• Track business expenses as they happen, not at tax time.

• Make estimated tax payments on schedule so you're not paying it all at once.

• Contribute to a retirement account when it makes sense for your situation — this can also reduce your taxable income.

• Talk with a tax professional about your business structure. For some business owners, particularly as income grows, an S-Corporation election can be worth exploring. This is an advanced strategy and not the right fit for everyone, so it's worth a real conversation rather than a general assumption.

The Bottom Line

Self-employment tax exists so that when you work for yourself, you're still paying into Social Security and Medicare — building toward the same benefits an employee earns through payroll withholding. The rate is higher, but with good records and the right planning, it's manageable rather than something to dread.

The goal isn't a perfect system overnight. It's a routine you can actually keep up with — one that gives you a clear picture of what you owe well before it's due.

Frequently Asked Questions

Is self-employment tax the same as income tax? No. Self-employment tax covers Social Security and Medicare. You'll also owe federal (and if applicable, state) income tax separately, based on your net income.

Do I owe self-employment tax if my business had a loss? Generally, no — self-employment tax is based on net earnings. If your business didn't have net income for the year, there typically isn't self-employment tax owed. Every situation is different, so this is worth confirming with your specific numbers.

How often do I need to pay it? Most self-employed individuals pay through quarterly estimated tax payments rather than one annual payment. Staying on that schedule helps avoid penalties and makes the amounts far more manageable.

Does forming an LLC change my self-employment tax? Not by itself. An LLC is a legal structure, not a tax election. Whether a different tax structure — like an S-Corporation election — makes sense depends on your income level and business specifics, which is a conversation worth having directly rather than assuming one way or the other.

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