Calculate self-employment tax (Social Security + Medicare) for freelancers with Schedule SE estimation and quarterly payment planning.
Freelancers usually assume the 15.3% self-employment tax applies to their full profit. It does not: Schedule SE charges it on net earnings from self-employment, which equals 92.35% of net profit, and that factor is where this calculator starts. Enter net profit after business expenses and it returns the Social Security and Medicare portions, the half of the tax deductible on Form 1040, and the per-quarter share for estimated payments. Two things surprise most first-time users: the 92.35% factor means the true rate on profit is about 14.13%, and if W-2 wages alone have already reached the annual Social Security wage base, the 12.4% Social Security portion of the tax on the self-employment earnings is eliminated entirely, leaving only the Medicare portion.
A concrete input and expected output from the current implementation.
Input
Net profit: $50,000. No W-2 wages.
Expected output
Social Security (12.4%): $5,725.70. Medicare (2.9%): $1,339.08. Total self-employment tax: $7,064.78. Deductible half: $3,532.39. Per-quarter share (SE tax only): $1,766.20.
The calculator applies the 92.35% factor first, so the 15.3% rate lands on $46,175 of net earnings rather than the full $50,000. Half of the $7,064.78 total is deductible on Form 1040, and the quarterly figure covers only the SE tax; income tax must be added on top.
Self-employment tax is not charged on net profit directly. The tool multiplies profit by 0.9235, the Schedule SE factor that backs out the employer-equivalent half deduction, to arrive at net earnings from self-employment. It then applies 12.4% Social Security up to the annual wage base and 2.9% Medicare on the whole amount. Below the cap, that is a combined 15.3%.
On top of the tax itself, the tool reports 50% of the SE tax as the above-the-line deduction on Form 1040, then divides the tax by four to suggest the self-employment portion of each estimated payment, due April 15, June 15, September 15, and January 15. The quarterly figure covers SE tax only; income tax and state tax must be added separately.
Schedule SE treats the self-employed person as both employer and employee. The 0.9235 factor backs out the employer-equivalent half of the tax before the combined rate is applied, so the tax is 15.3% of 92.35% of profit, about 14.13% of profit in practice. Every self-employment tax computation uses this factor, and it comes from the IRS Schedule SE worksheet.
Not once combined earnings pass the annual Social Security wage base, which was $176,100 in 2025 and is adjusted each year. Below the cap both portions apply; above it, only the 2.9% Medicare portion applies to further self-employment earnings. Include your W-2 wages when you run the calculator, and confirm the current base with the Social Security Administration.
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