Self-employment tax is the single biggest financial surprise for new freelancers. The numbers look great on the invoice; they look much worse after tax. The good news: SE tax is mechanical once you understand it. This is the plain-language version — what it is, how it works in 2026, what you can deduct, and how much of every payment to set aside so April does not break you.
What Self-Employment Tax Actually Covers
SE tax is the freelancer's version of payroll tax — the Social Security and Medicare contributions that W-2 employees split with their employer. As a freelancer, you pay both halves yourself. The combined rate is 15.3% (12.4% Social Security + 2.9% Medicare) on the first $176,100 of net earnings in 2026, then drops to 2.9% (Medicare only) above that threshold.
Important: SE tax is on top of federal income tax. A freelancer earning $100K of net profit pays roughly $14K in SE tax AND $14K to $18K in federal income tax — combined federal burden of $28K to $32K before state. Add state tax (0 to 13%) on top.
The Calculation Walkthrough
The IRS uses a quirky formula: SE tax applies to 92.35% of your net earnings, not the full amount. So for $100,000 net profit, taxable SE earnings = $92,350, SE tax = $92,350 × 15.3% = $14,130.
Federal income tax then applies to your adjusted gross income, which is net earnings minus half of your SE tax (deductible) minus your standard or itemized deduction. For a single filer in 2026 with $100K net: AGI = $92,935, taxable income = $77,935 after standard deduction, federal income tax = $12,820. Combined federal: $26,950.
If that feels like a lot, it is. Plan for 25-30% of every payment going to federal tax, plus state. Use the free Self-Employment Tax Calculator linked below to see your specific numbers.
Deductions That Lower Your SE Tax Base
Every legitimate business expense reduces your net earnings, which reduces both SE tax AND federal income tax. The compound effect is meaningful — a $1,000 deduction saves roughly $300-$400 in combined federal tax for most freelancers.
- →Home office (regular and exclusive use): square footage method or simplified $5/sqft up to 300 sqft.
- →Software, hardware, subscriptions used for business.
- →Health insurance premiums (above-the-line deduction).
- →Retirement contributions: SEP-IRA, Solo 401(k), traditional IRA.
- →Education, professional development, books.
- →Mileage (current IRS rate) or actual vehicle expenses for business travel.
- →Professional services: accountants, lawyers, software contractors.
- →Meals with clients (50% deductible).
The Quarterly Payment Schedule
If you expect to owe $1,000+ in federal tax for the year, the IRS requires four estimated tax payments: April 15, June 15, September 15, and January 15 of the following year. Missing payments triggers underpayment penalties (currently ~8% annualized).
Easiest approach: calculate your expected annual tax, divide by 4, pay each quarter. The Self-Employment Tax Calculator shows your quarterly amount directly.
When an S-Corp Election Makes Sense
Once net profit consistently exceeds $50,000-$80,000, an S-Corp election can save meaningful SE tax. The mechanic: pay yourself a reasonable salary (subject to payroll tax), take the rest as distributions (not subject to SE tax). Savings are typically $5,000-$15,000/year for freelancers in the $100K-$200K profit range.
Trade-offs: more paperwork, payroll processing, separate tax return, higher accountant fees ($1,500-$3,000/year). The math usually works at $80K+ net profit. Consult a CPA before electing — it is not a DIY decision.
How Much to Set Aside per Payment
The simplest rule: on every client payment, immediately transfer 25-30% to a separate savings account. At year-end, you have your tax liability covered. State tax adds 0-13% on top depending on jurisdiction.
For a $5,000 invoice: $1,250-$1,500 goes to the tax account, $3,500-$3,750 lands in your operating account. The discipline of doing it on payment day (not "later") is what makes this work.
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Frequently Asked Questions
Do I have to pay SE tax on every dollar I earn?
No — SE tax applies to net earnings after deductions, not gross revenue. A freelancer with $120K revenue and $30K expenses pays SE tax on $90K net profit, not the full $120K.
Can I avoid SE tax by working through an LLC?
A single-member LLC by default is treated as a sole proprietorship for tax purposes — same SE tax. The exception is electing S-Corp status (LLC or corporation), which lets you split income between salary and distributions. See the S-Corp section above.
What if I have a W-2 day job AND freelance income?
You still pay SE tax on freelance net earnings, but the Social Security portion only applies up to the combined wage base ($176,100 in 2026). Your W-2 Social Security counts toward that cap, so high earners may avoid the Social Security portion on freelance income — Medicare portion still applies fully.
Do I need to pay SE tax if I lose money?
No SE tax on a net loss. You may still owe income tax on other income (W-2, investments). Losses can offset other income and lower overall tax burden, but talk to a CPA — there are rules around what counts as a deductible loss vs hobby income.