Business Operations

Self-Employment Tax: Complete Guide

Sole proprietors and single-member LLCs pay SE tax on top of income tax. Most operators underestimate their total liability by 15–20%.

Estimate only. Consult a tax professional for filing.

What Self-Employment Tax Is

SE tax covers Social Security (12.4%) and Medicare (2.9%), totaling 15.3%. As an employee, your employer pays half. As a self-employed person, you pay both halves — on 92.35% of your net profit (the 7.65% reduction accounts for the "employer half").

SE Tax Base = Net Profit × 0.9235

SE Tax = SE Base × 0.153

Example: $120,000 profit → $110,820 base → $16,955 SE tax

Three Deductions That Reduce Your Bill

SE Deduction (50% of SE tax)

You deduct half of your SE tax from gross income before calculating income tax. This mirrors the employer-side deduction employees receive.

$16,955 SE tax → $8,477 deduction from gross income

QBI Deduction (20% of qualified business income)

Most self-employed operators can deduct 20% of net business income, further reducing taxable income. Subject to income phase-outs above ~$191k.

$120,000 profit → $24,000 QBI deduction

Standard / Itemized Deduction

2024 standard deduction is $14,600 for single filers, $29,200 married filing jointly.

$14,600 further reduction in taxable income

2024 Federal Tax Brackets (Single)

$0 – $11,60010%
$11,601 – $47,15012%
$47,151 – $100,52522%
$100,526 – $191,95024%
$191,951 – $243,72532%
$243,726 – $609,35035%
Over $609,35037%

These are marginal rates. Income in each bracket is taxed at that bracket's rate only.

Quarterly Estimated Payments

Self-employed operators must pay estimated taxes quarterly or face underpayment penalties. Total annual tax divided by 4 gives your quarterly payment.

Q1 (Jan 1 – Mar 31)Due April 15
Q2 (Apr 1 – May 31)Due June 15
Q3 (Jun 1 – Aug 31)Due September 15
Q4 (Sep 1 – Dec 31)Due January 15 (next year)

Effective Rate Benchmarks

$50,000 net profit~20–24% effective rate
$100,000 net profit~26–30% effective rate
$150,000 net profit~30–34% effective rate
$250,000 net profit~35–38% effective rate

Rates include SE tax and federal income tax. State taxes not included.