Self Employment Tax Guide

Self-employment (SE) tax funds Social Security and Medicare through the self-employed taxpayer's version of FICA. For many freelancers, sole proprietors, and independent contractors, it applies to net profit from a trade or business—not to W-2 wages, which use payroll withholding instead.

On a federal return, SE tax is generally computed on Schedule SE and reported with Form 1040. It is separate from federal income tax, though the two interact when calculating adjusted gross income.

IRS rules may require SE tax when net earnings from self-employment reach $400 or more in a tax year. Common situations include Schedule C profit, many single-member LLC owners treated as sole proprietors, and certain partnership or LLC profits subject to SE rules.

• Freelancers and independent contractors with net profit
• Sole proprietors filing Schedule C
• Many owners of disregarded single-member LLCs
• Some partners and LLC members (entity rules vary)

Entity classification, passive income, and S corporation W-2 wages follow different rules not fully covered here.

For 2025, the combined SE tax rate is 15.3% on net earnings from self-employment after the Schedule SE adjustment:

• Social Security portion: 12.4%
• Medicare portion: 2.9%

TaxChecker uses these documented rates in its Self-Employed Tax and 1099 Tax calculators. Your actual liability may differ if IRS caps, additional Medicare tax, or other return items apply.

Schedule SE does not multiply SE tax by 100% of Schedule C net profit. Instead, net earnings from self-employment use a 92.3% factor—commonly described as the 92.35% adjustment—before applying Social Security and Medicare rates.

Example for planning: $100,000 Schedule C net profit × 92.35% ≈ $92,350 net earnings base before rate application (simplified illustration only).

Social Security tax applies only up to the annual wage base. For 2025, that cap is $176,100 of combined wages and net self-employment earnings. Medicare tax generally continues above the cap; high earners may also owe additional Medicare tax under separate thresholds.

Federal income tax allows a deduction for approximately 50.0% of SE tax—the employer-equivalent share—when calculating adjusted gross income. This may reduce income tax but does not remove the SE tax itself.

A simplified federal planning flow looks like this:

• Start with net business profit (Schedule C or equivalent)
• Compute SE tax on adjusted net earnings (Schedule SE)
• Deduct the employer-equivalent portion of SE tax for AGI
• Subtract standard or itemized deductions to reach taxable income
• Apply federal income tax brackets to taxable income

TaxChecker models this sequence for estimate-only planning. Credits, other income, alternative minimum tax, and state taxes are outside scope.