Self-Employment Tax: The 15.3% Most 1099 Earners Underestimate
Last updated: April 2026 | Covers tax year 2025
Why this shocks new freelancers
When you work for an employer, 7.65% of your paycheck funds Social Security and Medicare (the "FICA" withholding) and your employer matches the other 7.65% behind the scenes. When you work for yourself, you pay both halves — 15.3% total, on top of your ordinary federal and state income tax. This is the single biggest reason first-year freelancers get hit with surprise tax bills in April: they budgeted for their income-tax bracket but forgot SE tax entirely. On $80,000 of net self-employment income, SE tax alone is over $11,300 before any income tax applies.
Source: IRS Sched IRS Sched SE (Self-Employment Tax) and Pub. 334 · Scope: federal payroll tax · 2025 Social Security wage base $176,100
How the 15.3% breaks down
SE tax has two components: 12.4% for Social Security and 2.9% for Medicare, totaling 15.3%. The Social Security portion stops at the annual wage base ($176,100 for 2025), so earnings above that cap face only the 2.9% Medicare tax. An additional 0.9% Medicare surtax applies to self-employment earnings above $200,000 ($250,000 for joint filers), with no upper limit. These thresholds aren't indexed to inflation, so more households drift into the surtax each year.
The 92.35% adjustment
Before applying the 15.3% rate, you multiply net self-employment earnings by 92.35%. This is a bookkeeping trick that approximates the employer's half of FICA being deductible — it ensures self-employed workers don't pay tax on the "employer-side" portion of their own tax. In practice this means the effective SE tax rate on net earnings below the wage base is about 14.13%, not 15.3%.
Above-the-line deduction for half
You can deduct 50% of the SE tax you pay as an above-the-line adjustment (Schedule 1, Line 15). This reduces your adjusted gross income but not your SE tax itself. The deduction is automatic — no itemizing required — and it's one of the few tax breaks that benefits taxpayers regardless of whether they take the standard deduction or itemize. It does not reduce FICA-equivalent owed, only income tax owed on the same earnings.
Quarterly estimated payments
Self-employed workers must pay SE tax (and income tax) through quarterly estimated payments, due April 15, June 15, September 15, and January 15 of the following year. Safe-harbor rules protect you from underpayment penalties if you pay either 90% of the current year's tax or 100% of last year's (110% if your prior-year AGI was above $150,000). For most freelancers, setting aside 25-30% of every client payment into a separate tax account is a simple rule of thumb that covers SE tax plus federal income tax at typical freelancer income levels.
S-corp election: the planning lever
Once net self-employment income consistently exceeds about $60,000, an S-corporation election can meaningfully reduce SE tax. An S-corp owner pays themselves a "reasonable" salary (subject to full payroll tax) and takes additional profit as a distribution (not subject to SE tax). The IRS watches aggressive splits closely — salaries must reflect market rates for the work performed — but disciplined use of the election can save several thousand dollars per year. The trade-off is added bookkeeping, payroll filings, and state franchise fees, so it rarely pays for income below the $60K threshold. Run the numbers with a CPA before electing.
Retirement accounts as an SE-tax offset
SEP-IRAs and Solo 401(k)s let self-employed workers shield large chunks of income from income tax (though not SE tax). A Solo 401(k) in 2025 allows up to $23,500 in employee deferrals plus roughly 20% of net SE earnings as an employer contribution, subject to the overall $70,000 cap. Because the contributions reduce AGI and marginal rate, combining a Solo 401(k) with a deliberate S-corp split is one of the most effective tax-planning playbooks for profitable one-person businesses.