Self-Employment Tax: The 15.3% Most 1099 Earners Underestimate

How the 15.3% rate 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; $184,500 for 2026, per the Social Security Administration's October 2025 announcement), 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 surtax 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) allows up to $24,500 in employee deferrals for 2026 (up from $23,500 in 2025) plus roughly 20% of net SE earnings as an employer contribution, subject to an overall cap of $72,000 for 2026 (up from $70,000 in 2025). 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.