What Is Self-Employment Tax And How Do I Calculate It

Self-employment tax is 15.3% of 92.35% of your net profit, covering Social Security and Medicare. You calculate it on Schedule SE by multiplying your net profit by 0.9235, then applying the 15.3% rate, but only the first $168,600 (for 2024) is subject to the Social Security portion.

How self-employment tax is calculated

You calculate it on Schedule SE by multiplying your net profit by 0.9235, then applying the 15.3% rate, but only the first portion of your earnings, capped at a threshold the Social Security Administration sets annually, is subject to the Social Security portion. Check SSA.gov for the current year’s contribution and benefit base before you run your numbers. For example, if your Schedule C shows $50,000 in net profit, you first multiply $50,000 × 0.9235 = $46,175, then multiply that by 0.153 to get $7,064.78 in self-employment tax. That $7,064.78 goes on Schedule 2, line 3, and then flows to your Form 1040, where you can deduct half of it (the employer-equivalent share) as an adjustment to income.

Why you don't pay on 100% of your income

The 92.35% rule exists because the IRS treats you as both employer and employee. When you work for a company, your employer pays half of your Social Security and Medicare taxes (7.65%) and withholds the other half from your paycheck. As a freelancer, you pay both halves, but the IRS lets you deduct the employer-equivalent half as a business expense. Rather than making you calculate that deduction separately, they simply say: only 92.35% of your net profit is subject to the tax. That 7.65% reduction is exactly the employer's share of the combined 15.3% rate (7.65% ÷ 15.3% = 50%). So if you see people online saying "you pay 15.3% of your income," they're wrong, you pay 15.3% of 92.35% of your income. This trips up many new freelancers who track their net profit in accounting software, see the 15.3% figure, and panic about owing more than they actually do. The same rule applies if you use a service like FreshBooks or QuickBooks for self-employment & freelancer taxes, the software applies the 0.9235 multiplier automatically, but you still need to understand why the number is lower than your gross profit.

The Social Security wage base limit

The 12.4% Social Security portion of your self-employment tax has a cap each year. Look up the current contribution and benefit base on SSA.gov, the figure the Social Security Administration publishes and adjusts annually, before you complete your return. If your net profit exceeds that year’s cap, you only pay the 12.4% on the capped amount of your *adjusted* net earnings. The remaining net profit is not subject to the Social Security portion at all. However, the 2.9% Medicare portion has no wage limit. On that same net profit, you pay 2.9% on the full adjusted amount. The IRS tracks this cap using Schedule SE Part I, line 4b, where you enter the wage base limit for the year. If you also have a W-2 job, the cap applies to your combined wages and self-employment earnings, so if your W-2 wages already hit the threshold the SSA sets, only the difference between that threshold and your W-2 wages is subject to the 12.4% rate. Confirm the exact limit at SSA.gov, then subtract your W-2 wages to find the taxable self-employment slice.

When the calculation breaks

The 15.3%-of-92.35% formula stops working in a few specific situations. First, if your net profit is under $400, you owe zero self-employment tax, you don't even need to file Schedule SE. This threshold applies to *net* earnings, not gross revenue, so if you made $500 but had $150 in legitimate expenses, your net is $350 and you owe nothing. Second, the formula fails for church employees who elected to be exempt from Social Security, they pay only the 2.9% Medicare portion, not the 12.4% Social Security part. Third, if your adjusted gross income exceeds the threshold the IRS publishes for your filing status, the Additional Medicare Tax kicks in at 0.9% on earnings above that threshold. Visit IRS.gov and search “Additional Medicare Tax” for the current income brackets before you file. This is not a flat addition to your self-employment tax, it applies to your *combined* wages and self-employment income, and it hits the employee portion only. So if you earn above the threshold from freelance work, you pay the standard 2.9% Medicare on the amount up to the limit, then 3.8% on the remainder. When this happens, the simple 0.9235 × 0.153 calculation underestimates your total tax, and you'll need to use Schedule SE Part II to calculate the additional amount. Also note that if you have multiple freelance gigs, you calculate self-employment tax on the combined net profit from all of them, you can't treat each client separately. And if you expect to owe more than $1,000 in total tax for the year, you'll need to make quarterly estimated tax payments to avoid penalties. When you're tracking your income, remember to fill out schedule c for freelance income first, because the net profit from Schedule C is what flows into Schedule SE, you can't calculate self-employment tax without it. As you track your business expenses, keep in mind what business expenses can freelancers write off, since those deductions reduce your net profit and therefore your self-employment tax.

Frequently Asked Questions

Do I pay self-employment tax if I have a full-time job and freelance on the side?

Yes, if your combined self-employment net earnings are $400 or more. Your W-2 job already withholds Social Security and Medicare, but that doesn't cover your freelance income. You'll calculate self-employment tax on Schedule SE, and the wage base limit applies to your total combined earnings. Before you file, pull your latest pay stub, note your year-to-date Social Security wages, and subtract that number from the SSA-published cap to see how much of your freelance income gets hit with the 12.4% portion.

Can I deduct health insurance premiums from my self-employment tax?

No, self-employment tax is calculated on net profit from Schedule C, and health insurance premiums are deducted later on Schedule 1 as an adjustment to income. They reduce your income tax but not your self-employment tax. Only the deductible half of self-employment tax itself lowers your adjusted gross income. Book the deduction on Schedule 1, not Schedule C, and keep your premium statements in case the IRS asks.

What happens if I forget to file Schedule SE and just report my freelance income on Schedule C?

The IRS will likely send you a notice with a bill for the unpaid self-employment tax, plus interest and possibly a late-payment penalty. The calculation is straightforward, they'll apply the 92.35% multiplier and the 15.3% rate automatically, but you'll owe the amount plus penalties. You can file an amended return to correct it, but you'll still owe interest from the original due date. Open the notice immediately, compare their math to your own Schedule SE draft, and pay the undisputed portion right away to stop additional interest from accruing while you prepare Form 1040-X.

You cannot find the Social Security wage cap or the Additional Medicare Tax income thresholds on a competitor’s tax-prep page because those figures are set and published exclusively by the Social Security Administration and the IRS, and we direct you to their official sources instead of quoting flat dollar amounts that expire. For a deeper dive into the full range of obligations and strategies, including estimated payments and deductions, turn to the broader topic of Self-Employment & Freelancer Taxes: What to Know and How to Handle It, where self-employment & freelancer taxes are explained in practical, up-to-date detail.