Paid on a 1099? Self-employment tax without the April surprise

Self-employment tax covers Social Security and Medicare when no employer withholds for you. How it’s calculated for 2026, worked examples, and how to avoid a surprise bill.

What it is

When you work for an employer, Social Security and Medicare taxes are split. Half comes out of your paycheck and the employer pays the other half. When you’re paid on a 1099, you cover both halves. That’s self-employment tax.

The rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare. It’s figured on Schedule SE and owed on top of regular income tax once your net earnings from self-employment reach $400 for the year.

Many new contractors budget for income tax and forget this piece entirely. On a modest profit it can be larger than the income tax itself, which is why the first April as a freelancer is so often a shock.

The 2026 numbers

Social Security portion: 12.4% on net earnings up to the 2026 wage base of $184,500. Earnings above that aren’t subject to the Social Security portion.
Medicare portion: 2.9% on all net earnings, with no cap.
Additional Medicare Tax: 0.9% on combined wages and self-employment earnings above $200,000 for single filers, $250,000 for married couples filing jointly, and $125,000 for married filing separately. These thresholds aren’t indexed for inflation.
Filing trigger: $400 of net earnings from self-employment for the year.

How the calculation works

Self-employment tax is based on net profit, not gross receipts. Every legitimate business expense on Schedule C reduces it.

The tax then applies to 92.35% of that net profit rather than all of it. That adjustment mirrors the fact that an employee isn’t taxed on the employer’s half of these taxes.

Finally, you deduct half of your self-employment tax when figuring adjusted gross income. That deduction lowers your income tax, not the self-employment tax itself.

Start with net profit from Schedule C (or your share of partnership earnings subject to SE tax).
Multiply by 92.35% to get net earnings from self-employment.
Apply 12.4% up to the wage base and 2.9% to all of it.
Deduct half of the result on your Form 1040.

Three worked examples

A consultant with $120,000 of net profit in 2026 and no other wages: $120,000 × 92.35% is $110,820 of net earnings. At 15.3%, self-employment tax is about $16,955. Half of that, roughly $8,478, is deductible when figuring adjusted gross income.

A single physician with $250,000 of 1099 profit: net earnings are $230,875. The Social Security portion stops at the wage base, so it’s $184,500 × 12.4%, or $22,878. Medicare is $230,875 × 2.9%, about $6,695. That’s about $29,573 of self-employment tax. The Additional Medicare Tax adds 0.9% on the $30,875 above $200,000, about $278, reported on Form 8959.

Someone with a $150,000 W-2 job and $100,000 of side-business profit: net earnings are $92,350. The W-2 wages already used up $150,000 of the $184,500 wage base, leaving $34,500 for the Social Security portion, or $4,278. Medicare on $92,350 is about $2,678. Total self-employment tax is about $6,956, roughly half of the $14,130 it would be without the W-2 wages.

What reduces it, and what doesn’t

Because the tax runs off net profit, the reliable way to lower it is to capture every legitimate business expense: equipment, software, business mileage, a qualifying home office, professional fees, and the like.

Some popular deductions don’t touch self-employment tax. Contributions to a SEP-IRA or solo 401(k), the self-employed health insurance deduction, and the qualified business income deduction all reduce income tax, but they’re taken after self-employment tax is figured. They’re still worth it; they just don’t help with this particular line.

Common mistakes

Most self-employment tax problems come from a handful of habits. Each one is easy to fix once you see it.

Budgeting only for income tax. A contractor in the 22% bracket who sets aside 22% of each payment will come up short, because self-employment tax sits on top of that.
Paying estimates off gross receipts or a guess. Base them on year-to-date net profit, and revisit after a big contract or a slow quarter.
Mixing personal and business spending. Expenses you can’t document are expenses you may lose in an exam, and each one lost raises both income tax and self-employment tax.
Ignoring the wage base when you have a W-2 job. Your tax software handles it, but your quarterly estimates may not, so you can overpay all year if you don’t account for it.
Assuming an LLC changes the answer. A single-member LLC that hasn’t elected S corp status is still taxed like a sole proprietorship, and its owner still pays self-employment tax on the profit.
Forgetting the state. Most states with an income tax expect their own estimated payments, on their own schedule.

Avoiding the April surprise

No one withholds for you, so the IRS expects you to pay as you go. If you expect to owe $1,000 or more when you file, you generally need to make estimated payments that cover both income tax and self-employment tax. Pay too little during the year and you may owe an underpayment penalty on top of the balance.

For calendar-year 2026, estimated payments were due April 15, June 15 and September 15, 2026, and the last is due January 15, 2027.
You generally avoid the penalty if your payments and withholding cover at least 90% of this year’s tax, or 100% of last year’s tax. The prior-year figure rises to 110% if last year’s adjusted gross income was over $150,000 ($75,000 if married filing separately).
Move a fixed share of every payment you receive into a separate tax account, so the money is there when a deadline arrives. For many contractors, 25% to 35% of each payment is a reasonable starting point, depending on income and state.
If you or your spouse also have a W-2 job, increasing withholding there can cover some or all of what you’d otherwise pay quarterly. Withholding is treated as paid evenly through the year, which can help if you’re catching up late.

What to gather each quarter

A 20-minute quarterly routine keeps estimates close to reality. Pull a year-to-date profit and loss statement from your books, note any W-2 wages and withholding for you or a spouse, and compare what you’ve paid so far with your safe-harbor target.

If profit is running well ahead of last year, the prior-year safe harbor still protects you from the penalty, but it won’t shrink the balance due in April. Setting aside the difference in your tax account avoids a large check at filing time.

When it’s time to look at an S corp

Once profit gets large, it’s worth asking whether an S corp election makes sense. S corp owners who work in the business pay payroll taxes on a reasonable salary and take the rest as distributions, which aren’t subject to Social Security and Medicare taxes.

The election isn’t free. It brings payroll, a separate corporate return, state fees in some places, and IRS scrutiny of the salary you set. The savings depend on your profit, your reasonable salary and your state, so run the numbers before electing. Tally Tax typically models both structures side by side before recommending a change.

Frequently asked questions

Do I owe self-employment tax if I lost money this year?

No. Self-employment tax is based on net earnings, and if those are under $400 you generally owe none. A loss from one business can offset profit from another business you run when figuring net earnings on Schedule SE.

Does self-employment tax apply to my full income or just my business profit?

Just net self-employment earnings. Interest, dividends, capital gains and most rental income aren’t subject to it. W-2 wages have Social Security and Medicare withheld separately, which is why they reduce the room left under the wage base.

Can a SEP-IRA contribution lower my self-employment tax?

No. Retirement plan contributions for the self-employed reduce income tax but are figured after self-employment tax. The same goes for the self-employed health insurance deduction.

I missed the September estimated payment. What now?

Make a payment as soon as you can. The underpayment penalty is figured like interest on the amount and time you were short, so paying sooner reduces it. Catching up on the January 15, 2027 payment still leaves an earlier shortfall, but it keeps the penalty from growing.

Why is my self-employment tax lower when I also have a W-2 job?

The Social Security portion applies only up to the annual wage base, $184,500 for 2026, and your W-2 wages count toward it first. Only the remaining room is taxed at 12.4% on your self-employment earnings. The 2.9% Medicare portion still applies to all of it.

This guide is general information, not tax, legal or accounting advice for your situation. Rules and inflation-adjusted figures change; confirm current-year details with a credentialed professional before acting.