Self-Employment Tax: The Bill Nobody Warned You About

When you were an employee, your pay stub had two neat deductions: Social Security and Medicare. Half came out of your paycheck. Your employer quietly paid the other half in the background. You probably barely noticed it was happening.

Now you work for yourself. Congratulations. You are both the employee and the employer now. Which means you pay both halves. All of it. Every dollar.

This is self-employment tax. It is not the same as income tax (that comes later, separately, as a bonus surprise). It is the bill that hits every freelancer, contractor, and independent business owner who did not know to budget for it during their first year.

The actual math

Self-employment tax is made up of two pieces:

There is one wrinkle. The IRS lets you calculate SE tax on 92.35% of your net income, not 100%. The reasoning is genuinely strange: it is meant to account for the fact that an employer's share of payroll taxes is a deductible business expense, and since you are your own employer, you get a partial adjustment. If this feels circular, you are not wrong. Just accept it and move on.

Here is what that looks like for someone with $100,000 in net self-employment income:

Not a rounding error. That is a real bill, due in addition to income tax.

Then income tax shows up

SE tax and federal income tax are calculated separately. You do not just add 15.3% to your income tax bracket and call it a day. They stack.

The one break: you can deduct half of your SE tax from your gross income before calculating income tax. The IRS acknowledges that employers deduct their share of payroll taxes as a business expense, so you get to do the same for your half.

Here is the full picture for that same $100K earner, filing single in 2025:

And that is before state income tax. California residents, add another 7-9% on top of that. Texas and Florida residents, enjoy your zero.

Why nobody warned you

When you were on payroll, your employer was silently paying half your Social Security and Medicare out of their operating budget. You never saw it. It never appeared on your pay stub. It was just part of the cost of having you as an employee.

Now that you work for yourself, you see the full cost clearly for the first time. The effective tax rate on freelance income is often 10-15 percentage points higher than what the same person paid as an employee at the same income level. The first tax April as a freelancer is a rite of passage nobody talks about enough.

The quarterly thing

The IRS does not want to wait until April to get paid. They want money throughout the year via quarterly estimated tax payments. The deadlines for 2026 are April 15, June 16, September 15, and January 15.

Miss them and you get hit with an underpayment penalty. It is not catastrophic (currently around 8% annualized on the unpaid amount) but it is annoying and completely avoidable.

The one long-term move worth knowing about

Once your net profit clears around $80,000, there is a tax structure worth looking at: S-corp election. The short version is that an S-corp lets you split your income into a salary and distributions. You pay SE tax only on the salary, not the distributions. On $150,000 net profit, this can save $10,000 to $15,000 in SE tax annually.

It comes with admin overhead (payroll, corporate tax returns, probably an accountant), so it only makes sense above a certain income level. There is a full guide on this in the Building Wealth section. For now, just understand where this tax comes from and make sure you are setting enough aside.