Freelance Tax Estimator

Self-employment tax exists because a sole proprietor is simultaneously the employer and the employee for Social Security and Medicare purposes. Schedule SE begins with net profit (gross receipts minus ordinary and necessary business expenses) and multiplies it by 0.9235. That factor is 1 minus 0.0765, the employer share of FICA, and it exists so the self-employed person is taxed on a base comparable to an employee whose wages already exclude the employer contribution. The resulting net earnings face 12.4 percent for Social Security up to the annual wage base (168,600 dollars for 2024) and 2.9 percent for Medicare with no ceiling, plus an Additional Medicare Tax of 0.9 percent above 200,000 dollars for single filers or 250,000 for joint filers. One half of the total is deductible above the line, reducing AGI before the ordinary 10, 12, 22, 24, 32, 35 and 37 percent brackets apply. The practical caveats matter more than the arithmetic. This is a federal estimate only: state and local income tax, the Section 199A pass-through deduction of up to 20 percent of qualified business income, child and education credits, and retirement contributions to a SEP-IRA or solo 401(k) all move the answer substantially. The IRS safe harbor is what actually prevents penalties - pay at least 90 percent of the current year liability or 100 percent of last year (110 percent if prior-year AGI exceeded 150,000 dollars) across the four due dates of April 15, June 15, September 15 and January 15.

The Social Security Act of 1935 covered wage employees only; the self-employed were excluded entirely until the Self-Employment Contributions Act of 1954 brought most sole proprietors and partners into the system, initially at a rate near 3 percent of net earnings. Medicare coverage was added by the Social Security Amendments of 1965 and took effect in 1966. For decades the self-employed paid a deliberately discounted combined rate, on the theory that they had no employer to share the cost. The Social Security Amendments of 1983, drafted after the Greenspan Commission report, ended that discount and phased the self-employed up to the full 15.3 percent by 1990. Congress paired the increase with the two adjustments still used today: multiplying net earnings by 92.35 percent and allowing a deduction for one half of the tax, so that the total burden approximated an employee plus employer combination rather than exceeding it. The Medicare wage cap was repealed by the Omnibus Budget Reconciliation Act of 1993, effective in 1994, which is why Medicare now applies to every dollar. The 0.9 percent Additional Medicare Tax came from the Affordable Care Act of 2010 and took effect in 2013. Quarterly estimated payments trace back further, to the Current Tax Payment Act of 1943, which created pay-as-you-go withholding; taxpayers without withholding file Form 1040-ES in its place.