Self-Employment Tax Rate Explained: The 15.3% You Need to Know About

You leave a full-time job to go freelance. Your first year goes reasonably well. You've been careful to track income and you have a rough idea of what you'll owe. Then you sit down with your accountant or open your tax software and discover a line item you weren't expecting: self-employment tax. A large one. If you need a baseline, start with our imported business supplies.

This catches a lot of people the first time. Not because self-employment tax is obscure or complicated, but because it doesn't show up on the tax tables most people are familiar with. It sits on top of income tax, and if you didn't plan for it, it can turn an anticipated refund into a balance owing.

Here's what it is, how it's calculated, and what you can actually do about it.

What Self-Employment Tax Actually Is

When you work as an employee, your paycheck reflects two separate tax obligations. You pay 7.65% of your wages toward Social Security (6.2%) and Medicare (1.45%). Your employer pays another 7.65% on top of that as a matching contribution. You never see the employer's portion in your paycheck, so it's invisible to you.

When you become self-employed, you are both the employer and the employee. The combined rate is now yours to pay: 12.4% for Social Security and 2.9% for Medicare, totaling 15.3%. This is self-employment tax, also called SE tax, and it is separate from income tax. You owe both.

The formal mechanism is that self-employed workers pay FICA taxes (the Federal Insurance Contributions Act taxes that fund Social Security and Medicare) at the combined rate that applies when no employer is splitting the cost. It is not a penalty for being self-employed. It is simply the full cost of funding those programs when you are on both sides of the employment relationship.

The Social Security Wage Cap

The Social Security portion of SE tax does not apply to all earnings indefinitely. There is a wage base limit that adjusts each year for inflation. For 2025, the Social Security wage base is $176,100. Earnings above that threshold are not subject to the 12.4% Social Security portion. The 2.9% Medicare portion, however, applies to all net earnings with no cap.

For most freelancers and self-employed workers earning under six figures, this cap is not relevant. But if you have a strong income year, it means your effective SE tax rate decreases as earnings exceed the wage base.

How the SE Tax Calculation Actually Works

The IRS builds a small adjustment into the SE tax formula that keeps things fair. Because employers can deduct their half of FICA as a business expense, the IRS gives self-employed workers an equivalent break. You calculate SE tax not on 100% of your net earnings, but on 92.35% of your net earnings. That 7.65% reduction approximates the employer's deductible portion.

Here's the full calculation for a freelancer with $70,000 in net self-employment income:

That $9,891 goes on Schedule SE and then onto your Form 1040. It is added to your income tax liability. You are not choosing between income tax and SE tax. You owe both.

The Deduction That Offsets Some of the Pain

Once you have calculated your SE tax, you get to deduct half of it from your gross income before calculating income tax. This is the IRS acknowledging that the employer half of FICA would be a deductible business expense if you were paying someone else's payroll taxes.

Using the example above: your $9,891 in SE tax generates a deduction of $4,945. That deduction reduces your taxable income, which means your income tax bill goes down. The deduction does not reduce the SE tax itself, but it softens the overall impact.

This deduction is claimed on Schedule 1 of Form 1040 and flows directly into your adjusted gross income. You do not need to itemize to claim it. It is an above-the-line deduction available to all self-employed filers.

What SE Tax Means for Your Set-Aside Rate

This is where most people's tax planning falls apart. They calculate their income tax and set aside accordingly. They don't account for SE tax as a separate line item, and the result is that their tax reserve comes up short.

Here's a realistic picture of what a freelancer earning $65,000 in net income actually owes:

These are approximations for a single filer taking the standard deduction with no dependents. Your numbers will vary. But the pattern holds: SE tax alone adds roughly 13-15% to your overall effective rate. That's the number that catches people.

SE Tax Starts at $400 in Net Income

SE tax applies once your net self-employment income hits $400 in a year. This threshold is low enough that even a small side project can trigger it. If you do occasional freelance work alongside a day job, you still owe SE tax on that income once it clears $400, even though you're also paying FICA through your employer on your primary income.

There's no proration based on your employee income. Self-employment income is taxed independently.

Can You Reduce Self-Employment Tax?

SE tax is calculated on net self-employment income, which means legitimate business deductions reduce your SE tax bill directly — not just your income tax. Every dollar of valid business expense reduces net income by a dollar, which reduces the SE tax base by 92.35 cents, which saves you roughly 14 cents in SE tax. At scale, this adds up.

Deductions that reduce SE tax include all standard business expenses: equipment, software, a business-use percentage of your phone and internet, home office costs, professional development, accounting fees, business insurance, and marketing expenses. None of these reduce the rate, but they all reduce what the rate applies to.

The S-Corp Strategy (for Higher Earners)

One approach self-employed workers use to reduce SE tax at higher income levels is electing S-corporation status. Here's the basic mechanics: as a sole proprietor, all net income is subject to SE tax. As an S-corp owner, you pay yourself a reasonable salary (which is subject to payroll tax), and any remaining profit is distributed as shareholder distributions, which are not subject to SE tax.

For example, if your business nets $150,000 and you pay yourself a $75,000 salary, payroll taxes apply to the $75,000. The remaining $75,000 is distributed as profit and is not subject to SE tax. The savings can be meaningful at that income level.

This strategy involves real setup and ongoing costs: S-corp formation, payroll processing, separate bookkeeping, and an accountant to ensure the "reasonable salary" determination holds up to scrutiny. It typically makes financial sense somewhere north of $50,000-$80,000 in net self-employment income, depending on your state. Below that, the overhead often exceeds the savings.

Quarterly Estimated Payments Include SE Tax

When the IRS asks for quarterly estimated tax payments, they mean the full amount: income tax plus SE tax. Both obligations are combined into your quarterly payment. If you are only estimating your income tax bracket and sending that in, you're likely underpaying.

The IRS quarterly deadlines are April 15, June 15, September 15, and January 15 of the following year. If you expect to owe $1,000 or more for the year, these payments are expected. Underpayment results in a penalty calculated as a percentage of the unpaid amount for each day it was late, typically annualized around 7-8%.

The safe harbor rule: if you pay at least 100% of last year's tax liability (or 110% if last year's AGI exceeded $150,000), you avoid underpayment penalties regardless of what you owe. This is a useful planning tool when income is variable.

Building SE Tax Into Your System

The practical solution is to treat SE tax and income tax as a single combined number when calculating your set-aside rate. Don't try to estimate them separately in real time.

A defensible approach for most freelancers:

1. Estimate your expected annual net income (revenue minus business expenses)
2. Calculate the SE tax component: net income x 92.35% x 15.3%
3. Look up your approximate federal income tax bracket and effective rate
4. Add your state or provincial income tax estimate
5. Add those three figures together and divide by your annual net income to get your combined effective rate
6. Set aside that percentage of every payment you receive, into a dedicated tax reserve account

Once you have done this calculation once, the system runs on autopilot. Update the estimate after each tax return, when you know your actual effective rate from the prior year.

If you want a starting point without doing the full calculation: 30-33% of net income is a reasonable conservative reserve rate for most US-based freelancers earning $50,000-$100,000 annually. It covers federal income tax, SE tax, and leaves a small buffer for state taxes in most jurisdictions.